Lavender Turning Brown & Withered?

Lavenders don’t look good in the rainy season anyway, especially if it rains for days on end. The bottoms of the plants turn black.
Lavender should be cut back around January. Cut only the young parts and do not cut into old wood. Cutting old wood can kill the plant. I usually only cut half the foliage off the lavender at a time, opening it up so light can get to the base. Once the new shoots appear on the cane and are growing well, then I cut of the rest of the foliage. If lavender is not pruned regularly, they get leggy and more woody with time. Cuttings can be rooted in perlite to produce more plants.
Check the pots, lavender starts to look bad when they are pot bound too. I pot up my lavender in pots usually up to a 5 gallon pot. They grow much bigger in the ground. They do like well drained soil and don’t care that much for fertilizer. I use osmocote. A scoopful of compost doesn’t hurt but make sure it does not pile up against the stem, it will rot the plant.
The type of lavender you have does matter. The lavendins are more heat tolerant than the lavenders. L. multifeda (fernleaf lavender) and L.dentata do best in zone 11 in full sun. L. augustifolia (zone 5-8) does o.k. in pots in cooler areas and summer afternoon shade.
Since your lavenders only have a single stem. I would check the pots to see if they need to be potted up. Remove all the dead brown leaves from the bottom of the plant. Pinch the top of the lavender to promote branching. At this time of the year they can be out in full sun in pots, but if it starts to rain heavily and for days on end, put the lavenders in a patio or under the eaves where they can stay a bit drier but still get good light until the rain stops. Check plants for water more often under the eaves, they get almost no water at all even in the pouring rain. I have more perlite in my media so I need to water lavender in pots every couple of days minimum. The lavender I have in the ground is planted on a slight slope and is about a year old. I do have a sprinkler system that waters for 5 min. every 4 days. I rarely water at all at this time of the year. In summer, I water deeply about once a week. I have red clay soil, so it holds on to water for a while. The lavender in the ground was cut back in February but it was a 3ft diameter mound and will get back to that size again by summer.

Lavender Deterioration/Concerns

Hi all,

Im not an experienced gardener but i know the basics to grow my my own fruit and veg, look after lawn in our little garden (which i’m quite proud of ) and other plants outside.
Usually a quick search online gives me the answers i’m looking for if a problem ever leaves me scratching my head! But i’m struggling with whats going on with my two lavender trees and wondered if anyone can help me out at all.

Ive had two planted in large pots since spring time, say around April and both have been doing really well, growing nicely with one blooming amazing purple spires which i’m just beginning to start cutting off. One variety is a Lavandula Ginginsii and the other i’m not too sure on, im guessing Hidcote.

As said, they have been really healthy plants, until we hit August! Within the last two weeks or so i’ve noticed deterioration in both plants which im concerned about as both me and the missus really like them and don’t want to lose them.
The Ginginsii has begun turning yellow from the inside, what was once lovely grey/green foliage is turning a sickly yellow. The tips of some leaves are starting to turn brown and crispy (like tip burn/scorch).
The other tree is going completely brown from the inside, again seems to start of with the scorch look and eventually this takes over the whole leaf. I began to pick the foliage off when noticing it but its certainly persisting!

Both plants receive lots of sun (when its out) and checking the soil, it doesnt seem overly wet. Ive even drilled more drainage holes in the bottom of the pots and gravel/stones was used in both pots when the trees were planted to aid better drainage.

ill post some pictures to see if it helps at all and see if anyone has any ideas. Or am i just worrying too much about them? Ive heard that lavender gets a bit “blergh” this time of year as it comes to the end of flowering.

any help guys would be great, thanks in advance

Lavender Plant Care: It Needs a Little Bit of Time and Expertise

Lavender plants look gorgeous, smell heavenly, and thankfully, are very easy to maintain. Caring for a lavender plant requires minimum hard work, a fraction of your free time, and minuscule amount of expertise in plant care.

Beautiful, purple, and divinely fragrant. There are a lot more words used to describe the beauty of lavender plants. Lavender is a valuable herb to have at home, with its uses ranging from beauty products, to medicines, to cooking. But, the best feature about this plant, besides its utility, of course, is that it is not a high-maintenance shrub as many imagine it to be.

What follows is a list of instructions that are simple to execute, and help you own a lavender bloom in all its glory.

Caring for Your Lavender Plant

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There are three widely known species of lavender, which are English lavender, French lavender, and Spanish lavender. However, it is the English lavender plant, that finds a place in most households across the world.

Before we begin, it is important to know the nature of this plant, which will go a long way in establishing an appropriate routine for plant care.

✔ Lavender plants thrive in dry weather.

✔ Humidity makes them susceptible to root rot.

✔ They need uninterrupted sunshine.

✔ The soil used to plant lavender should be gravelly, and not too moist.

Planting Lavender

How to plant lavender?

✿ The best option is to pick a potted plant or a plant cutting, which can be sourced from any plant nursery.

✿ You can also plant lavender using seeds, but it may not result in a good yield.

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Let’s Work Together!

✿ You can choose to plant it in a pot, or in your garden. Ensure that the soil is well-drained and gravelly.

When is the best time to plant it?

✿ Summers are ideal, for the simple reason that lavender needs a lot of sunlight. Do not plant lavender in any shaded areas of your garden. If you’re keeping it indoors, place it on a windowsill, where it gets enough sunshine. If you live in areas with very hot temperatures, ensure that you keep the plant in a shady place during the afternoon to protect it from burning.

Which soil type is recommended?

✿ Dry, gravelly, and alkaline soil is the best option to plant lavender. Since it is a drought-resistant plant, it does not need soil that retains moisture. It is recommended to mix the soil with some amount of sand to make it more dry.

How is the watering routine?

✿ Lavender plants typically do not need a lot of watering. You may water it deeply, not more than three times a week. Feel the soil to make sure that it is not too damp on the days that you haven’t watered it. Any residual moisture around the roots can cause root rot. Keep in mind that although lavender can withstand dry and hot weather, it can dry out and die due to lack of moisture. So keep the plant well-hydrated, but do not drown it.

A few tips

✿ Lavender is not a favorite among pests, so the use of fertilizers is hardly required. Watch out for fungal infections that may affect the plant if the air becomes humid. This can be avoided by keeping the soil well-drained.

✿ Pruning is mostly done in the fall or the spring seasons, beginning in its second year. Just make sure that you lightly trim the foliage (not more than one-third of the plant’s size), without making the plant bald. Do not chop any old, woody sections of the plant, as it may affect the growth.

✿ You may want to add a little bit of potash on to the plant’s base in the spring and at the end of summer to help it grow. If your plant is turning yellow in appearance, it suggests an imbalance in the soil’s pH levels. Adding compost will sort out this problem.

✿ Although these plants are fond of dry weather, they need plenty of air. Therefore, indoor lavender plants need to be kept in areas that are airy.

Caring for a lavender plant does not require a lot of effort, or any specific gardening skills. So, follow these simple tips and enjoy your lavender plants in their full bloom every year.

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Hawthorn Leaf Spot

The fungus Entomosporium mespili (asexual stage) causes hawthorn leaf spot.

Host Plants

Hawthorn leaf spot affects Crataegus laevigata (especially, ‘Paulii’ English hawthorn) severely.

Description

Initially numerous small red-purple spots develop on infected leaves, green twigs and fruit. Several weeks after infection the often coalesce into purplish-gray-brown blotches. By mid-summer the leaves turn prematurely yellow and drop from severely infected trees.

Disease Cycle

Hawthorn leaf spot survives the winter in lesions on green twigs and fallen leaves. In the spring, rainfall splashes spores from fruiting structures onto developing leaves. Cool rainy conditions maintain leaf wetness and favor spore germination and penetration of leaves and green shoots. Fruiting structures arise in leaf spots and repeating cycles of spore production occur throughout the spring and summer.

Management Strategies

Collect fallen leaves to reduce the amount of inoculum available to initiate subsequent spring infections. Prune and space trees well to increase air circulation and sunlight penetration so foliage dries quickly. If irrigating the trees avoid wetting the foliage and water early in the day so leaves dry rapidly in the afternoon. Where hawthorn leaf spot is a persistent problem, grow resistant hawthorn species such as Crataegus crusgalli (cockspur hawthorn) and Crataegus phaenopyrum (Washington hawthorn). Fungicides protect developing leaves and twigs in the spring on susceptible high value trees. Begin applications when buds break open and repeat at labeled intervals as long as the weather is cool and wet.

Written by: Dan Gillman
Revised: 09/2011

Photo: R. K. Jones, Diseases of Woody Ornamentals and Trees. APS Press.

Why Are Leaves Turning Brown And Falling Off On My Indian Hawthorne?

Maple Tree · Gardenality Genius · Zone 10A · 30° to 35° F
Hi Joe-Are these shrubs older and well establish or fairly young shrubs? When did you prune the shrubs and were they pruned back quite a ways to control their size? Do you remember is you had any cold or freezing temperatures after the pruning? The indian hawthorn, which is what i’m assuming you have, are extremely hardy and can accept any hard pruning even rejuvenation pruning within 6 inches of the ground and recover well. I’m thinking at this time your pruning may not have had anything to do with the plant browning and losing leaves. Were any of the leaves yellowing or browning prior to your pruning? Have you had a lot of rain that may have kept the soil saturated for a period of time. Has there been any fertilizing of this plant or any weed killers or other chemicals used for any reason nearby? Check the leaves closely for any damage to the leaves or appearance of any insects. Discoloration and spotting, before browning and dropping could indicate insect or disease causing the browning and dropping of leaves. Evergreen shrubs such as these will also lose many of there older leaves this time of year especially more so with some plants after the unusually cold winter many have had. Scratching small spots through the outer bark with a sharpe knife or fingernail and observing the tissue under the bark will indicate whether the stems are still alive or not. If the tissue under the bark is green and not brown the limb is still alive. If brown that part of the stem is dead. If you could upload a picture of the shrub and a close up picture of the affected leaves it may help to lead us to the problem. To the right of your name below your question you will see where you can upload your pictures.

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Brown Leaves on Weigela – Knowledgebase Question

There are several possible reasons for this to be happening, but the most common would be either overwatering or underwatering. Although you have been watering every day, it is possible that the water has not penetrated the root ball. Sometimes the potting soil is very difficult to rewet if it has been allowed to dry out. It will also take some time for the roots to spread into the surrounding soil. Use your finger to test the soil near the base of the plant about an inch down to see if it is moist. A slow, deep watering about twice a week is better than a daily light sprinkling. Also, a daily light sprinkling, especially if done in the evening so it keeps the foliage moist longer, can contribute to foliar problems. Finally, you may be overwatering the plant. The soil should be moist but not sopping dripping wet with standing water. (The reason for this is that plant roots need air as well as moisture.) A few inches of organic mulch spread around the plant (but not touching the bark) is also a good idea as it will help maintain soil moisture and temperature as well as hold down weeds. If you fertilize the shrub, be sure to read and follow the label instructions carefully; however, your shrub needs time to establish itself in the new location before you can expect it to grow at full speed. Most plants suffer a certain amount of transplant shock when planted during hot weather so keep an eye on the watering and give it a little time to adjust. Good luck with your shrub!

Pest & Disease Control for Weigela

Every plant has the future potential for disease and insect damage. Factors such as location and weather will play a part in which issues your plants encounters. If available, disease-resistant varieties are the best option for easy care; and for all types of plants, proper maintenance (such as watering, pruning, spraying, weeding, and cleanup) can help keep most insects and diseases at bay.

NOTE: This is part 4 in a series of 7 articles. For a complete background on how to grow weigela, we recommend starting from the beginning.

Aphids

They are the size of a pinhead and vary in color depending on the species. Cluster on stems and under leaves, sucking plant juices. Leaves then curl, thicken, yellow and die. Produce large amounts of a liquid waste called “honeydew”. Aphid sticky residue becomes growth media for sooty mold.

Natural Control

  • Sometimes you can knock them off with a strong stream of water from your garden hose.

Chemical Control

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer
  • Bonide® Systemic Rose & Flower Care

Euonymous, Lilac, Nannyberry

  • Bonide® Total Pest Control

Leaf Spot

Appears as black or brown spots on underside of leaves. Often the center falls out leaving a hole with a red halo. Leaves may turn yellow and fall.

  • Serenade® Garden Disease Control

Flowering Shrubs

  • Bonide® Copper Fungicide Spray or Dust

Privet, Hydrangea

  • Bonide® Fung-onil™ Fungicide

Leafroller

Pale yellow or ‘dirty’ green worms. Leaves are rolled and webbed together where insects feed. Eventually becomes ‘skeletonized’.

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer
  • Bonide® Total Pest Control

Spider Mites

Pinpoint size, many different colors. Found on undersides of leaves. Severe infestations have some silken webbing. Sap feeding causes bronzing of leaves.

Natural Control Hardy Shrubs (thrives with minimal care) * Bonide® All Seasons® Horticultural & Dormant Spray Oil

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • Bonide® Total Pest Control

Mealy Bugs

Adults are 1/4” long, flat, oval shaped with a white waxy covering. Yellow to orange eggs are laid within an egg sac. Crawlers are yellow to brown in color. Over winters as an egg or very immature young in or near a white, cottony egg sac, under loose bark or in branch crotches, mostly found on north side. Damage is by contamination of fruit clusters with egg sacs, larvae, adults and honeydew, which promotes growth of black sooty mold.

Hardy Shrubs (thrives with minimal care)

  • Bonide® All Seasons® Horticultural & Dormant Spray Oil
  • Bonide® Systemic Rose & Flower Care

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer
  • Bonide® Total Pest Control

White Fly

Adults are tiny, white winged insects found mainly on the underside of leaves. Nymph emerge as white, flat, oval shapes. Larvae are the size of a pinhead. Suck plant juices from leaves causing them to turn yellow, appear to dry or fall off plants.

Hardy Shrubs (thrives with minimal care)

  • Bonide® All Seasons® Horticultural & Dormant Spray Oil
  • Traps
  • Bonide® Systemic Rose & Flower Care

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • Bonide® Total Pest Control

Bagworm

Bagworms are the larvae of moths. Brown bags up to 2 inches long and composed of bits of dead foliage, twigs and silk are often seen attached to twigs and inside is a dark brown or black caterpillar. Adult female moth is wingless and the male has wings. Severe infestations can defoliate an entire plant often killing evergreens such as arborvitae and cedar but may only slow the growth of a deciduous plant.

Ornamentals

  • Bonide® Thuricide® Bacillus Thuringiensis (BT)

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer
  • Bonide® Total Pest Control

Tent Caterpillar

Hairy caterpillars that enclose large areas in webbing and feed on enclosed leaves. Remove web with rake and burn. Caterpillars are pulled out with webs.

Ornamentals

  • Bonide® Thuricide® Bacillus Thuringiensis (BT)

Euonymus, Lilac

  • Bonide® Borer-Miner Killer
  • Bonide® Total Pest Control
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Anthracnose

Very small, round, brown spots appear first on lower, older leaves. Plants gradually lose leaves from bottom upwards. Other symptoms may include black, sunken spots on leaf stalks, light brown to pale yellow lesions on cane, black fly speck-like spots on green berries.

  • Serenade® Garden Disease Control
  • Fall clean up of fallen leaves and other debris, pruning out infected twigs.

Euonymus

  • Bonide® Fung-onil™ Fungicide

Powdery Mildew

Whitish-gray powdery mold or felt-like patches on leaves and green twigs. Leaves may crinkle and cup upward. Over winters in fallen leaves.

  • Serenade® Garden Disease Control

Viburnum

  • Bonide® Fung-onil™ Fungicide

Botrytis Gray Mold

The fungus thrives in cool, moist conditions. Usually begins on plant debris, weak or inactive plant tissue, than invades healthy plant tissue. Causes spotting and decay of flowers and foliage, tissue becomes soft and watery. Affected parts of plant could wilt and collapse. If humidity remains high a grayish-brown coating and spores develops over the surface of the collapsed tissue.

  • Serenade® Garden Disease Control
  • Good sanitation will help avoid the problem.
  • Remove and destroy dead leaves, flowers and dead plants.
  • Water the plants at soil level and not on foliage.

Black Spot

Disease causing defoliation and black spots on leaves and thrives in moist conditions. Twigs may also be infected. Black spots are circular with fringed margins, if severe, spots can combine to cause a large black mass, can weaken and kill plants.

  • Remove and destroy dead leaves, flowers and dead plants.
  • Water the plants at soil level and not on foliage.

Euonymus, Privet, Spirea, Hydrangea (foliage only)

  • Bonide® Fung-onil™ Fungicide

Downey Mildew

Yellow spots on leaves with downy spots on underside of foliage. Older leaves in center of vine are infected first. Can infect fruits, become soft, grayish, wither, may or may not have downy symptom. Over-winters on fallen leaves, so fall clean up is vital.

  • Serenade® Garden Disease Control
  • Remove and destroy dead leaves, flowers and dead plants.
  • Water the plants at soil level and not on foliage.

Rust

Most common on fern growth after harvest. Infection begins in spring and produces orange stage of disease and is occasionally found on new spears. Yellow or pale orange pustules in concentric ring pattern. Spores are airborne to new fern growth where brick red pustules are formed on all parts of the fern. Ferns may turn yellow or brown, defoliate and die back. In fall the spores turn black and will over winter. Rust causes reduced plant vigor and reduced yields.

  • Serenade® Garden Disease Control
  • Remove infected plant parts and destroy.

Hydrangea (foliage only)

  • Bonide® Fung-onil™ Fungicide

Thrips

Tiny, slender, fringed wing insects ranging from 1/25 to 1/8” long. Nymphs are pale yellow and highly active and adults are usually black or yellow-brown, but may have red, black or white markings. Feed on large variety of plants by puncturing them and sucking up the contents.

  • Bonide® Systemic Rose & Flower Care

Euonlymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer (exposed)
  • Bayer Advanced™ Complete Insect Killer (exposed)
  • Bonide® Total Pest Control (exposed)

Fall Webworm

Damage the leaves by both feeding and web building. Webworms over-winter within cocoons located in protected places, such as crevices in bark or under debris and fences. Adult moths emerge in summer. They have a wingspan of about 1 1/4″ and vary from pure satiny white to white thickly spotted with small dark brown dots. Females lay white masses of 400-500 eggs on the undersides of the leaves. The caterpillars hatch in 10 days and all from the same egg mass live together as a colony. They spin webs that enclose the leaves, usually at the end of a branch, to feed upon them. After they have defoliated a branch, they extend their nest to include additional foliage.
When caterpillars are mature, they leave the nest to seek a place to spin gray cocoons. The mature caterpillars are about 1 1/4″ long with a broad dark brown stripe along the back, and yellowish sides thickly peppered with small blackish dots. Each segment is crossed by a row of tubercles with long light brown hairs.

  • Prune webbing as it appears.

Ornamentals

  • Bonide® Thuricide® Bacillus Thuringiensis (BT)

Nannyberry, Lilac

  • Bonide® Borer-Miner Killer

Japanese Beetle

Adult is metallic green beetle, which skeletonizes leaves. Larvae are a grub, which feeds on turf roots. This is more of a problem east of the Mississippi River.

  • Bonide® Systemic Rose & Flower Care (adult)

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

Locust

Large (up to 1½ inches long) dark bodied insects with wings. Young insects hatch and enter the soil, where they burrow to the roots. Immature locust suck sap from roots and adults may suck sap from young twigs. Female lays eggs in the sapwood of twigs, causing the leaves on damaged twigs to turn brown. Twigs may break and fall to the ground eventually.

  • Cut off and destroy injured twigs.
  • Maintain good tree vigor by watering and fertilizing plants.

Euonymus, Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • Bonide® Total Pest Control

Cutworm

Large (vary from ½ -2” long) fleshy, hairless caterpillars. Adult cutworms are dark, night flying moths with bands or stripes on their forewings and lighter color hind wings. Some feed on the stems, others feed on new tender growth. Cutworms feed at night and can destroy a new plant over night.

Nannyberry, Lilac

  • Bonide® Borer-Miner Killer

Armyworm

Newly hatched worms are white with black heads. Mature worms are light tan or dark brown with dark or orange back and side stripes. They feed on the leaves of plants.

Lilac, Nannyberry

  • Bonide® Borer-Miner Killer
  • GardenTech® Sevin® Concentrate Bug Killer
  • Bayer Advanced™ Complete Insect Killer

In This Series

  • Introduction

Getting Started

  • Planting

Care & Maintenance

  • Fertilizing
  • Pest & Disease Control
  • Pruning
  • Spraying
  • Watering

How should I treat a weigela bush with a large section of dead branches?

I have two weigela bushes which have been healthy for at least five years. (That’s how long we’ve lived here, so I can’t say their exact age.) I don’t know the specific variety, but it has variegated leaves and pink flowers.

I’m in Northeast United States, Zone 6 (−10 °F, −23.3 °C ), and they’re quite hardy. They bloom for a month or so beginning in May, and again when the weather cools off in September or October. The leaves remain beautiful for many months, often beyond the first frost. Twice a year, after the flowers drop, we prune them to maintain a shape and size we like. We leave the bottom leggy because it’s a resting place for small birds we wouldn’t otherwise see.

It’s currently mid-May, and one is becoming more lush and full of leaves each day, and budding on schedule. The other has many brown, brittle branches which appear to have died. Some look totally lifeless, while others are bare at the base and tip, but have some off-shoots in random mid-sections which have new foliage and the beginnings of buds.

A close examination doesn’t reveal any unusual growths or mold on the wood, although the picture on the bottom right does show some stripping on a section of an older branch. The new leaves are free of bite marks, curling, discoloration, or anything I generally associate with insects. There are no holes around the base, so I don’t think chipmunks, squirrels or rabbits or our other usual visitors have been digging at the roots. There are some shriveled looking leaves in sections of the dead wood, but I’m pretty sure they’re left over from last year, as that’s common and happens to both plants.

The bushes are a few feet apart in the same soil, which we don’t treat with anything, especially pesticides. They experience the same weather conditions. The shape of the affected one hasn’t been altered, and none of those branches have snapped beyond what we pruned. In fact, up until the other plant behaved as expected, we assumed they were both fine, just preparing for the spring. I waited before becoming concerned as I thought it might just be running behind the other in terms of timing. Sadly, though, I see no signs of life at all on the affected branches.

The brown sections are brittle and easy to break off, although I haven’t done so, because I’m awaiting advice. I’ve considered cutting off the totally unproductive branches and pruning back the others to the point of the new growth. However, a friend told me the plant is using all its energy to produce growth in general, and those scattered sections may be doing more harm than good. Obviously I’m going to lose symmetry either way, although I suppose I could prune the other to match! My bigger concern is the future of the bush.

What should be my next course of action?

Click on pictures for larger size.

Update as of August 2016, three months after the original post: We partially tough-loved it, meaning we cut down all the dead sections to the root level, and left the rest alone. It was lopsided and looked silly (still does because we haven’t trimmed it), but it grew back already, and even has a flower!

Large sections of the outer branches on my holly bush have brown, dried leaves this spring. It was fine in the fall, but now I’m finding all these brown leaves. What’s going on?

Occassionally in spring homeowners may find dead, reddish-brown foliage on their needle evergreen plants, such as pine, spruce, fir, juniper, arborvitae and yew, on on their broadleaf evergreens, such as holly and mahonia. The extent of the symptoms can vary from brown needle tips on one side of the plant, to one or two branches, to the whole tree. Injury is found on the outer portion of the branches and is often most severe on the side of the tree facing the wind or a source of radiated heat, such as a south or west-facing brick wall or street.

Winter desiccation is a common type of winter injury that occurs when the amount of water lost by the foliage exceeds the amount picked up by the roots.All trees lose water during normal metabolic processes, even in winter. During the growing season when trees are in full foliage, large amounts of water are lost through their leaves. During winter months, photosynthetic processes are slowed, but evergreens continue to lose water at a higher rate than deciduous trees, through their needles and to a lesser extent from exposed bark, twigs and buds.

Warm, sunny days or windy conditions increase the amount of water lost from the needles. If the soil is frozen or soil moisture is low due to dry conditions, plant roots are unable to pick up enough water to meet its needs. Needles dry out and die, but they may hold their green color until warmer temperatures arrive in spring, thus delaying the onset of browning symptoms.

Winter wind accompanying dry periods can accelerate water loss from the needles, and needle death is more extensive on the side of the tree facing the prevailing wind. Other common terms for this type of injury are winter burn, winter drying or winter scorch.

When water usage exceeds available water, the needles, leaves and twigs dry out and die. Usually evergreen leaves or needles hold their green color even after the injury has occurred until warm spring temperatures arrive, resulting in delayed browning symptoms. Affected needles turn yellow or reddish-brown at the tip, and dieback to the base.

Often the pattern of damage is directional, on one side of the tree more than the other. Wind accompanying dry periods can accelerate water loss from the plant and result in damage that is more extensive on the side of the tree facing the prevailing wind, particularly those with southern or western exposures.

Another factor that can contribute to a directional pattern of browning is solar radiation reflected from hard surfaces such as brick siding, pavement, light-colored metal siding or white lava rock mulch. Evergreen trees planted along streets may show browning of the foliage nearest the roadway. Foundation plantings of yew, juniper, dwarf Alberta spruce and arborvitae located around buildings show browning on the side next to the house.

Factors that can predispose evergreen trees to winter desiccation are 1) white or lava rock around the base of the tree; 2) poorly develop root systems due to improper planting; 3) girdling roots; 4) root injury; 5) soil compaction; 6) stress due to insects or disease; and 7) tree genetics, i.e., trees from a southern United States source.

Management

No immediate action should be taken with evergreen plants showing winter injury other than supplemental watering if conditions are dry. Evergreen trees with a small amount of needle loss may still have live buds within the damaged branch sections. These buds will send out new growth and eventually fill in the damaged section in a few years. Evergreen shrubs, like holly and mahonia, may regenerate new leaves to replace the damaged foliage if injury was not severe enough to kill the underlying branches.

Pruning- Wait until new growth has emerged before pruning out dead branches. After the new growth has emerged, prune out any dead branches or branch tips, cutting back to 1/4″ above a live bud. It is important to remove dead branches. They can provide an entryway for insects or fungi that attack the dead tissue.

Summer watering- The key to preventing winter desiccation is to maintain adequate soil moisture throughout the summer and into winter. Provide damaged plants with one inch of water per week, allowing them to growth vigorously and avoid further injury next winter. Trees that have suffered from drought conditions at any time during the year will not be able to withstand dry winter conditions as well as trees that have consistently received adequate moisture.

Winter watering- Many people put their water hoses away for the winter, but periodic watering during the fall and winter at times when the ground is not frozen can be very beneficial. Trees and shrubs benefit from slow, deep watering with a hose that has been left to trickle for an hour or so. Turfgrasses also benefit from a periodic deep watering.

Mulching- Apply a 3-6 foot diameter ring of mulch around the base of trees and shrubs, with 3-4 inches of an organic material like coarse wood chips. This helps conserve soil moisture and prevent deep freezing of the soil in winter.Relocation- Susceptible trees and shrubs may be protected from prevailing winter winds next year by erecting a lath or burlap screen on the south or southwest side in fall, or by transplanting them to a more protected location.

Loss of trees due to winter injury is unnecessary and costly, not only in monetary terms, but in intangible values such as shade, protection and beauty. Since Nebraska frequently experiences dry fall and early winter conditions, deep-watering trees in fall may mean the difference between healthy, vigorous trees or stressed, struggling trees next spring.

Good drainage essential for healthy pittosporums

  • Root rot and a variety of fungi can cause the leaves of pittosporums to turn brown. Root rot and a variety of fungi can cause the leaves of pittosporums to turn brown. Photo: Courtesy Photo

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Q: The variegated pittosporum hedge on the left front of my house is dying. The leaves are turning brown, and some of the branches are brittle. The same type of pittosporum hedge is on the right front of my house, but the plants are fine. Both hedges are exposed to the same amount of sun/shade and water. What can cause the death of one hedge and not the other? What solutions might reverse this dying stage, short of buying new pittosporums?

Leon Richardson, Houston

A: Root rot or another fungal disease could be the problem, especially given the heavy rains the past year and a half. This year, plants have been stressed, first by a long, soggy period followed by a horrid hot, dry spell, and now more rainy weather.

Root rot can plague pittosporum. Plants can wilt and die. So good drainage is essential, as these shrubs don’t tolerate extended periods of wet roots. Avoid irrigating during rainy periods. Improve drainage by amending the soil with compost and clean, sharp sand, if needed. Note that soils along house foundations often go unimproved, leading to poor drainage and in turn, poor root health.

Several fungi can trigger dieback, a fungal problem that causes browning leaves and branches to die from the tip back. Prune these infected areas out, sterilize your clippers with a bleach solution between cuts. You may see blackened or gray discoloration in damaged branches. Cut back to healthy, green wood. With good drainage, a healthy soil and adequate sun, your shrubs may rebound.

However, if the entire crown of a plant is affected, you could lose the plant.

Some treat dieback with a fungicide, but many experts say that’s not worth your time and advise focusing on improved culture.

Q: I was discouraged by the early-summer appearance of sod webworm moths in my garden and, in turn, a large area in my lawn damaged by their caterpillars. The moths appeared late last summer and lingered into the fall, so now that more populations are here, I need to give into treatment after avoiding it for years. Is there an organic treatment that is safe for birds, earthworms, toads, butterflies and dogs?

Susie McMichael, Houston

A: Several gardeners have reported this nuisance in recent weeks. Bacillus thuringiensis spray is a treatment for various caterpillars, and it can be effective in battling the night-feeding larvae (caterpillars) of the sod webworm moth. The white-gray moths can be seen skimming over the lawn in early evening. The moths lay their eggs on grass, and once hatched, the larva/caterpillars live in silken tunnels built in the thatch of the grass. The caterpillars chew off pieces of grass and return to the small tunnel to eat. You may see the silky tunnel threads in early morning.

Apply the Bt spray according to label instructions. Avoid spraying butterfly plants.

Texas A&M University experts say the webworms prefer sunny, hot, dry lawn areas, so water these deeply as needed. Cut the grass high during hot, dry periods. Gather the clippings during infestation as the moths lay their eggs on the grass blades.

Use an organic fertilizer.

Q: I’d like to move some lycoris planted in a garden bed. Is it too late to do so without forfeiting next year’s blooms?

Dave Sherron, Houston

A: Ideally, we divide and transplant lycoris (spider lily) bulbs after the foliage yellows in spring. But you could move these trusty heirlooms now, keeping as much soil/roots intact as possible. Or, since it’s so close to bloom time, you could move them after they flower and before the foliage emerges. Keep in mind that divided, replanted and even newly bought and planted bulbs may take a year to establish and bloom.

Delicate-looking but indestructible spider lilies, L. spp., are Asian amaryllids with 4- to 6-inch umbels of narrow petals and long stamens perched on 18-inch stems. The strappy foliage emerges after the blooms, lingers into spring and dies down with summer’s heat.

The red L. radiata is the most dependable and common species, a drought-tolerant heirloom found in abandoned landscapes. But the glowing white L. x albiflora and peppermint L. x incarnata also adapt in the Houston area.

Plant lycoris in sun or part sun from late spring to fall among ground covers, in mixed borders and in pots.

Note: The exotic spider lily and the oxblood lily share the common name hurricane lily because both bloom at the height of storm season.

Q: My 20-year-old crape myrtle isn’t looking as well as it should. I’ve noticed that there are many more suckers than usual. Is this a problem? I keep taking them off, to no avail. Do you have any suggestions that would help keep this plant alive for many more years?

Hilary Thompson, Missouri City

A: Crape myrtles can send up suckers from the base of the trunk, and if these are not removed, the crape can gradually lose its tree form and look more like a full shrub. We’ve had so much rain, many plants are growing unchecked, but many also show signs they’re stressed by wet conditions.

Continue to remove the suckers as they appear. These can steal nutrients from the main plant. Prune each all the way back to where it originates. Make a flush cut, and don’t not leave a stub, or soon several more suckers will replace the one you removed.

Some people slow sucker regrowth by treating fresh cuts with a sucker stopper product. Ask your nurseryman for suggestions.

Check the drainage to make sure the crape roots are not struggling in an oxygen-depleted, soggy soil. You might apply an organic fertilizer this fall or early spring to improve nutrients and encourage healthy growth. Mulch with a quality compost.

Ask an Expert

The fungus is able to infect new areas by several means. Very rarely the spores of the fungus are dispersed through the air and land on dead wood surfaces and initiate infection. More commonly the fungus will be introduced into an area by the transportation of infected material such as the transplantation of infected plants, contaminated roots, or contaminated mulches. Hygiene is obviously important in minimising the spread of this fungus as the fungus survives in infected plant debris.
Drought is often associated with severe symptoms. It appears that the stress involved predisposes the tree to infection and also allows the fungus to more rapidly colonise the root system of the plant. Similarly stresses resulting from flooding can also predispose trees to severe infection. It is fair to say that any factor that stresses trees is likely to result in a weakened defence system and an increased likelihood of the disease developing.
The fungus can survive in soil for extremely long periods of time and there are estimates of survival for up to 50 years.
Control
At present there is no one simple method for controlling Armillaria luteobubalina. A combination of sanitation measures, good horticultural management and the addition of organic matter to soils can be expected to retard the activity of Armillaria.

How Can I Save Pittosporum Tenuifolium?

Answer #1 · Maple Tree’s Answer · Hi Leon-A picture of the white spots on the trunk and leaves browning would help to identify the problem. Whether the white spots have any thing to do with the browning and dropping of leaves we first need to identify the spots. Leaves browning and dropping could be caused by too little or two much water. Is the soil by chance too dry or possibly too wet from irrigation or rain? When digging down approximately 8 inches in spots around the trees the soil should feel cool and moist but never too wet or dry. I would check the area around the dead tree first. Has there been periods of a lot of rain at times. Too wet a soil can cause root rot and or several fungal diseases that can cause leaves to yellow, brown, and drop with the tree eventually dying. If soil stays saturated for a period of time Pittosporums growing in hot humid conditions can develop a fungal infection known as Southern Blight. This is a soil born fungi that moves up the trunk from the soil. As this fungi moves up the trunk and stems it coats them with a white mycelium (fungus). Unfortunately treatment of this fungal infection involves the removal of the infected tree and fumigation of the soil. Insects such as white scale can infest pittosporums. These hard shelled insect can be found on the stems and leaves of the tree. They feed on the juices of the leaves eventually turning them brown. White spots or patches on the trunk could also be lichens. There are several types of lichens that can be white, tan, brown, or black and is a growth that is often seen on many trees. The lickens growth is normally associated along with the appearance of moss or algae. The lichens only attach to the bark of the tree and do not feed off the tree. They are not harmful to the tree. As you can see there are several things that can cause the white spotting on the tree. As I noted the spotting and browning of the leaves may be caused by a single pest or disease or possibly the spotting may not be associated with the browning and dropping of the leaves. If the white spots look like white tooth picks protruding from the bark these would be made by the Ambrosia beetle which can attack many trees and shrubs such as the pittosporum. This beetle bores throught the bark and into the sapwood depositing a fungi that they and their larvae feed on. The fungus they deposit into the trees wood is harmful along with the disruption of the trees nutrient flow because of the boring damage and can eventually kill the tree. The white tooth pick looking protrusions are the sawdust plugs that are pushed out as the beetle bores into the bark. Above this answer and to the right of your name below your question you will see where you can upload any pictures you have saved on your computer. I noted a link to an article that will explain the lichens. I also uploaded a few pictures showing the lichens, Southern Blight, scale insects, and deposits left by the Ambrosia beetle. Let me know if any look like what you are seeing and upload any pictures if you like that would show the white spots and browning leaves up close.

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