Purple Shamrock

Botanical Name: Oxalis regnellii

Purple Shamrock grows in a clump habit of striking purple foliage. Its triangular-shaped leaves fold along the vein and look like butterflies fluttering above slender stems.

Many varieties are available, including ‘Triangularis’ pictured here. Other common names for this plant are False Shamrock and Shamrock Plant.

You can expect an abundance of soft-pink flowers to appear in spring and summer. Dainty, five-petaled blooms rise like trumpets above the mounds of purple, clover-like leaves.

Don’t let its fragile appearance deceive you. This is one of the easiest flowering house plants to grow as long as you can keep it moist and shaded.

Oxalis plants may go dormant if the soil is allowed to dry out or if it’s exposed to hot, direct sun. Don’t worry, it will come back. Just cut off all the leaves and you’ll have a healthy, thriving plant in just a few weeks.

Divide this plant or repot it anytime. Use a pot with drainage holes to prevent soggy soil. If you want to use a decorative pot without drainage holes, use it as a cachepot. Just slip a plain nursery pot into the cachepot. I put pebbles in the bottom of cachepots to keep the plant above the drainage water.

This happy-go-lucky plant seems content to be anywhere. You can grow Purple Shamrock indoors year-round, or move it outside on a shady patio for the summer. It can be planted outdoors in frost-free regions, but it’s fast-spreading and can be invasive in the garden.

Purple Shamrock and Supplies

Purple Shamrock Care Tips

Origin: Brazil

Height: 6-12 in (15-30 cm)

Light: Bright indirect light will give O. regnellii the best leaf color. Leggy, spindly growth is often caused by lack of light. Move the plant to a spot where it will get curtain-filtered light from a south-facing window.

Water: Allow surface of soil to dry between waterings. Don’t allow the potting medium to dry out. Oxalis is sensitive to the salt buildup from fertilizers. You’ll notice it as whitish deposits on the surface of the soil or around the rim of the planter. It’s a good idea to flush the soil occasionally to rid the soil of excess salts, which can harm this plant’s fleshy roots. Flush the pot every month or two by watering plants thoroughly with room-temperate water. Allow the water to drain through the drainage holes for a half-hour. Then flush it again. Empty the drainage tray afterward so that the plant is not sitting in water.

Humidity: This Brazilian native prefers relative humidity around 50% or higher. If indoor air is dry, try one of these easy ways to increase humidity for your plant.

Temperature: Prefers cool temperatures, especially while in bloom; 55-65°F/13-18°C at night/not warmer than 75°F/24°C during the day.

Soil: Any good potting mix

Fertilizer: Feed every 2 weeks while plant is growing with a balanced liquid fertilizer diluted by half. When blooming stops, feed every other month.

Propagation: Divide the plant by gently pulling apart its small, tuberous roots into smaller clumps and potting them in separate containers.

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Shamrock Houseplants: How To Grow A Potted Shamrock Plant

If you’re decorating for a St. Patrick’s Day party, you’ll want to include a potted shamrock plant or several shamrock houseplants. But party or not, the potted shamrock plant is an attractive indoor plant. So what is a shamrock plant? Keep reading to find out more about growing and caring for shamrock plants.

What is a Shamrock Plant?

The potted shamrock plant (Oxalis regnellii) is a small specimen, often reaching no more than 6 inches. Leaves are in a range of shades and delicate flowers bloom off and on during fall, winter and spring. Leaves are clover shaped and some think the plant brings good luck. These leaves fold up at night and open when light returns. Also known as the lucky shamrock plant, growing Oxalis houseplant is simple and adds a touch of spring to the indoors during winter months.

Shamrock houseplants are members of the wood sorrel family of the genus Oxalis. Caring for shamrock plants is simple when you understand their periods of dormancy. Unlike most houseplants, the potted shamrock plant goes dormant in summer.

When leaves die back, the potted shamrock plant needs a time of darkness to rest. Caring for shamrock plants during the period of dormancy includes limited watering and withholding of fertilizer.

The dormant period when growing oxalis houseplant lasts anywhere from a few weeks to three months, depending on the cultivar and the conditions. New shoots appear when dormancy is broken. At this time, move shamrock houseplants to a sunny window or other area of bright light. Resume caring for shamrock plants to be rewarded with an abundance of the attractive foliage and blooms.

Growing Oxalis Houseplant

When shoots appear in autumn, begin watering the newly growing Oxalis houseplant. Soil should remain lightly moist during times of growth. Water two to three times a month, allowing soil to dry out between waterings.

Fertilize after watering with a balanced houseplant food.

Shamrock plants grow from tiny bulbs that may be planted in fall or early spring. Most often, shamrock plants are purchased when foliage is growing and sometimes when in flower. Many cultivars of oxalis exist, but exotic varieties provide the best indoor performance. However, don’t dig a wild wood sorrel from outdoors and expect it to grow as a houseplant.

Now that you’ve learned what is a shamrock plant and how to care for a growing Oxalis houseplant, include one in your indoor collection for winter blooms and maybe good luck.

Oxalis (Purple Shamrock / False or Love Plant)

Purple Shamrock Care Guide


Oxalis is not overly fussy with its light requirements. The species with purple leaves will take less bright areas than its all green leaf cousins.

However for a good looking plant you’re going to want an area which receives bright light, or even some sun for a few hours a day. Don’t overdo the sunshine though, too much sun will damage the leaves.

The leaves move throughout the day, often turning to face light sources. During the day with good light hitting the leaves, they should open wide and then as the day draws to a close the leaves close slightly. If you’re not seeing any movement with the leaves at all, then it could be an indication that the plant is in a dark position and needs a bit more light.


Ideally soak the soil and then allow the top inch or so to dry out before watering again. Although irregular and random watering is not a problem here, in fact the plant can often go months without adverse effects especially when it’s cooler.

If it’s very warm or it sits in a very bright spot you will need to make an effort to water regularly, because if things get too dry the plant will die back.


A misting once in a while to help keep the leaves free of dust would be appreciated. But the Purple Shamrock is easy going when it comes to humidity levels and so there is no need to worry about it or mist on a regular basis.


Feeding only needs to be done infrequently, so using an all purpose fertiliser at normal strength once every couple of months is plenty.


As a houseplant, you don’t need to worry about the temperature level very often. If given the choice they they do prefer cooler spots in your home, but will still do okay in warmer living spaces. However in very warm rooms, or spaces that heat up, like those near a window you need to be careful. If the temperature gets above 25°C (77°F) on a regular basis it will very quickly “age” the plant and make it look ragged and unattractive.

Sitting in a very warm room, will quickly “age” the plant

You might not think your house gets this warm, but window ledges with full sunlight beaming through can become serious heat spots pretty quickly so be careful.

Try to keep it in a location that has average levels of warmth. The plant will even do quite well in cooler places to like an unheated porch or hallway. Just don’t expose the plant to sub zero temperatures and it will be fine.


Because the Purple Shamrock is reasonably compact, repotting only needs to be done every few years. Perhaps when the plant has spread to all sides of the pot or you want it to become more bushy. In any case, a general all purpose compost will be absolutely fine as long as it has good drainage.


Creating new plants is really easy to do. In most pots there are many many bulbs of which a small section of the overall plant belongs. All you need to do is divide the “clump” and plant the bulbs up in different containers, the new “clump” will produce more bulbs and gradually fill its new home.

Try not to keep the bulbs too close together when you are repositioning them in their new pot(s), if you spread them over the container’s surface it will create more space and give the appearance of a fuller plant faster.

No matter what anyone tells you, you really don’t need any fancy compost or soil, just use a potting mix that is similar to what the bulbs were growing in previously. Keep the pot reasonably warm and reduce watering until the bulbs have established fully and are producing new shoots.

Speed of Growth

New growth is rapid. Once Purple Shamrock has become established or there is no space for it to grow into, it will slow down. At this stage you can either repot or divide your Oxalis, or leave it alone to keep the compact nature.

Height / Spread

Expect a max height of 25cm / 10in and it will spread to fill the size of the container you have put it in. A large wide container will mean a wide overall plant (see the first photo at the very start of the article to see how wide yours could get!).


The flowers are generally white with purple and pink hues mixed in. Like the plant itself, the flowers are also dainty and they form in small clusters which last for several weeks sitting a few inches above the leaves.

They could bloom at anytime of the year, however it’s normal to expect them to appear only in the Summer. Once the blooms start to die down, it’s best to carefully snip them off as close to the base as possible. If you don’t, they will dry out and become stringy before falling onto the leaves below and making them look messy.

Is the Purple Shamrock Plant Poisonous?

Although Oxalis is toxic it has a very bitter taste to repel anything or anyone who tries to eat it, and this is often enough to deter dogs and cats from eating more than the occasional mouthful. However, when ingested in large quantities it can result in poisoning in cats, dogs and humans.

The bulbs are where the highest concentration of the toxic compounds can be found, so in theory they’re hidden from view beneath the soil. You’ll need to decide if you have a pet or child that doesn’t give plants a second glance or one that’s always nibbling or playing with them. If the latter you’ll need to grow your Shamrock out of sight or consider growing something more pet friendly in its place.

Mars the cat is only curious but Oh My Plant keeps an eye on him just in case

Anything Else?

Although tolerant, if your treatment of the Purple Shamrock is anyway close to brutal you will quickly force it into die back mode, known more correctly as dormancy. This results in everything above the soil dying and taking shelter in the bulbs which sit just below the soil.

All is not lost however, because the plant will resurrect itself if the conditions improve. In many cases die back has happened because you have not watered it in months, so if you soak the soil, the plant should kick start back into life pretty quickly. The comments from many readers at the bottom of this article show this method works and that this is one tough cookie of a houseplant.

How to Care for a Shamrock Summary

  1. Good Light Levels Some sun will be helpful if possible, but it’s not essential. Deep shade and no light locations need to be avoided.

  2. Average Watering Water well and then wait until the soil is almost dry before watering again.

  3. Temperature Average to cool room temperatures are preferred. Very warm temperatures will result in distorted growth.

  4. Feeding Feed once every couple of months.

  • Do not try to grow it in a dark location
  • Never warmer than 25°C (77°F)

Purple Shamrock Problems

Leaves keep moving and changing position

Not a problem but rather a natural quirk of the plant. The leaves move in response to light. They “open” wide in high light (i.e. during the day) and “close” at low light levels (i.e. at night). They also move if you touch the leaves, although a lot lot slower than a Venus Fly Trap or Tickle Plant.

Die back / Dormancy

Again this is normal although not inevitable, so if you want to avoid it, treat your Purple Shamrock right and follow the care instructions we’ve provided above.

White spots on Purple Shamrock leaves

White Spots on your Oxalis plant can be caused by several different things and it will depend on how many spots, how extensive they are etc. Below are some suggestions with tell tale signs to look for.

  • Pests – It could be the waste products or damage from something like an Aphid infestation. The pests themselves should be easily to spot and the marks will only exist near to where the pests actually are
  • Fungus – A type of fungi such as Powdery Mildew can sometimes affect your plant if you keep it outside during the summer or next to an open window. Although quite simple to treat, this will be dense stuff which spreads to cover large sections of the leaf and can make things look worse then they are.
  • Sun Damage – Can cause white spots on the leaves. However unlike a fungus, these spots can typically be quite crusty and basically crumble away when touched, where as Powdery Mildew won’t do this.
  • Virus – This is the worst case scenario because there is no cure. Sometimes pests will visit your plant and take a bite, spreading a virus that will spread to the majority of the bulbs growing in the pot. You can trigger die back and remove all the foliage above the soil. However if you really have a virus problem when the new bulbs spring back to life the white and markings will come back too.

The first three problems above can be sorted out without too much fuss, but the final possibility means there is no cure as the bulbs become carriers of the virus. The markings on the leaves can be really disfiguring and ruin the look of these elegant plants, so in this instance it’s worth considering replacing the entirety of the existing bulbs with new ones. Be sure to use a different pot (or scrub the old one clean) and use fresh compost to stop the virus spreading to the new bulbs.

Weak and lankey looking plant

If temperatures are quite warm for prolonged periods, it hasn’t been repotted for ages, or has generally only received below average care for many months the plant might start to look a bit rubbish. If this ever happens you could be better off here withholding water completely so the plant goes into dormancy.

When this has happened wait a few more weeks before you resume watering again. When you do, the bulbs will quickly grow new shoots and the plant will be restored just like magic! (Although not instantaneously and not really by magic because it’s nature really ;- ).

About the Author

Tom Knight

Over the last 20 years Tom has successfully owned hundreds of houseplants and is always happy to share knowledge and lend his horticulture skills to those in need. He is the main content writer for the Ourhouseplants Team.

Also on Ourhouseplants.com

Credit for several Oxalis triangularis photos – Article / Gallery – KENPEI
Credit for Single Oxalis leaf – Article / Gallery – Oh My Plant
Credit for Mars the Cat – Article / Gallery – Oh My Plant

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Low-Maintenance Houseplants: Oxalis Triangularis

If you don’t possess the greenest of thumbs, don’t worry! There are plenty of low-maintenance houseplants that thrive with just minimal care, and we’re happy to highlight some of them for you.

First up is the oxalis triangularis. The oxalis family is large and varied, including some rampantly invasive varieties than have given oxalis a bad rep as “garden thugs,” but don’t be too quick to judge all varieties by the bad behavior of a few relatives! Many oxalis varieties are entirely well-behaved and a delightful addition to your home and garden. With varieties hardy in all climates in the United States, there are two that are also good choices for growing indoors as long-lived houseplants – oxalis triangularis and regnelli. Though both are hardy outdoors in zones 6-11, they adapt well to indoor conditions and thrive indoors year round. With its fanciful and intriguing purple foliage, let’s take a closer look at oxalis triangularis.

Oxalis Triangularis Origins

Oxalis triangularis are often referred to as “purple shamrocks.” The plant’s history can be traced back to St. Patrick, who held a similar plant and used the three leaves to explain the concept of the Holy Trinity to the Irish. Oxalis triangularis are not Irish natives, however – instead, they hail from Brazil.

Special Traits

Oxalis triangularis are highly “photophilic,” which means that they open and close not just their blooms, but also their leaves in response to light. At night, neatly folded, oxalis triangularis looks like a cluster of little purple butterflies that then open wide to the morning light. Both the vivid purple color of its leaves and this constant slow motion seems to enchant all who grow it – even “non-gardeners” fall in love this charming beauty. To capitalize on its unusual coloring, containers in silver or chartreuse are especially effective.

Incredibly long lived, oxalis triangularis often become “heirloom plants” passed down from generation to generation within a family. We often hear customers’ stories of the plants becoming a cherished family tradition. One customer told us she was enjoying the same bulbs as their great, great-grandmother who harvested them as a child 107 years ago! Since oxalis triangularis are super simple to plant and grow, they are frequently given as gifts. Choose one of our many pre-planted oxalis gifts, or take it easy on your wallet and make a nice gift by planting four triangularis in an empty soup can with the label removed. Once these are growing, the look is wonderful between the metallic can and deep purple foliage! Let the gift recipient know that these plants have the potential to become treasured, living family heirlooms that will last for generations with little care.

Be aware that oxalis triangularis has developed a natural toxicity to protect it from foraging animals. This is a plant that bites back, so take care with pets and small animals.

Basic Care

Oxalis triangularis bulbs look like small, immature pinecones. When planting a container for indoors, go ahead and crowd your bulbs, spacing them just an inch apart for a full look fast. Just poke the bulbs into the soil – any way up is right. Water lightly just once every couple of weeks until new growth appears. In about 6 weeks from planting, your new purple shamrocks will begin to appear, and will fill in to become lush and full soon after. Weekly watering should be light. Too much water will send the plant back into dormancy.

Indoors, keep your oxalis triangularis in a sunny spot. You will find the deep purple foliage really brings out the vibrant green of other plants, and the color contrast makes your other houseplants seem to glow with health.

Please note that oxalis triangularis occasionally go dormant, looking like the entire plant has died. Because this happens generally during the summer every 2-7 years when the plant is indoors, it seems like a serious problem rather than a periodic event. There is no need to toss your beloved triangularis! Simply stop watering and let the soil thoroughly dry. Set the plant aside where it is no longer center stage, but where you will still see it. In a few weeks, you will see a new leaf emerge. That is the time to resume watering. Soon, your purple shamrocks will be lush and full again.

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Grow oxalis triangularis for a long-lived, easy care houseplant with extra charm. Enjoy your purple shamrocks!

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The care and feeding of purple-leaf shamrocks

The purple-leaf shamrock, Oxalis triangularis, is a low-growing foliage plant for the garden that also makes for an attractive indoor plant with rich, vibrant, purple leaves. Smart gardeners have gravitated to this beautiful foliage plant to add color indoors and outdoors for several decades.

This Brazilian native came to the United States in the 1980s and its popularity continues to grow. Indoors, it can fill a pot with rich, purple leaves and add a dash of color to the often green indoor plant world. It is actually multiple small plants that grow as a group from bulbs. It has minimal needs, but one thing it cannot tolerate is overly wet soils. It is critical that the plant is in a container with a drain hole and is not overwatered. If this shamrock is exposed to temperatures above 80 degrees, it can wilt and go dormant. Michigan State University Extension horticulture educators and hotlines receive calls about the mysterious shutdown of a previously vigorous shamrock.

Outside, purple shamrocks are put into areas that are somewhat shaded. Because they are not much taller than 6 inches, they need to be in the front of the bed to be seen, or they could be in a container that needs season-long color. When the weather is warm and there is adequate moisture, the shamrock blooms with small, pale pink, bell-like flowers. By fall, the happy shamrocks will have multiplied themselves. Now, it’s time for the big decision. They can be dug and put into a pot and play the role of an indoor plant during the winter, or it is possible to store them like other summer bulbs in a dormant state and reactivate them in the spring.

If the shamrock is going indoors as a growing plant, dig the plant in mid-September before any frosts. This keeps the foliage looking good. Place into a container with a drain hole and water well to settle the soil. When the shamrock is indoors, place in a sunny window. The plant can handle more sunlight indoors because the windows filter out some of the light, and the days are growing shorter so there is less light intensity. The windows that usually have the most sunlight are, in order, south, west, east and avoid north because there may be none at all.

If the bulbs are going to be stored for the winter, dig chunks of roots and bulbs and gently remove as much soil as possible without having the chunks of tightly packed bulbs break apart. Place into a cardboard box and bring into the house until the foliage dies down and dries up. You can find small bulbs, called pips, or you may find short, fat, carrot-shaped tubers with bigger plants that had a great growing season. Once the foliage has dried up, cut off close to the soil surface. This might take a week or so. Store the clumps of bulbs in a container like a cardboard box or paper bag and nestle them into a bed of dry sphagnum peat moss, Canadian peat, wood shavings or vermiculite. The peat has the extra advantage of being acidic and preventing any rots if they should start. Root clumps should have a buffer of packing material under around and over them. This will slow drying of the bulbs. Place the container somewhere that is going to be dark and the temperature should be between 40 and 50 degrees. Cool and dark conditions keep them dormant. Freezing is fatal.

In the spring when all danger of frost has passed, which is usually from the middle to late May, plant the stored clumps about 1 inch beneath the soil and water well. It will take four to six weeks for the new growth to begin. Your indoor shamrock can be freed from its pot to run wild again.

Oxalis Triangularis

The false shamrock native to Brazil has picked up it’s common name from the Irish shamrock symbol which refers to a triangular three leaved plant or the clover. These are often sold and bought as gift pot plants, especially just before St Patrick’s day.

Two interesting aspects of this plant is it’s photonastic response, which is it’s reaction of opening up its leaves during the day and closing at night. And, the other is that it’s known as an edible plant, although there seems to be a lot of discussion about the amount of oxalic acid having negative effects on humans, so I think would rather stick to vegetables to be safe.

While this page is about growing this plant indoors it’s also possible to grow it outdoors in the correct conditions. Your shamrock grown indoors can enjoy the summer period outdoors; in a cool shaded spot, is best.

Flowering: Lot’s of small trumpet shaped blooms sitting above the leaves appear during spring and summer, which you can expect to last a fair few weeks.

Level of care: Most indoors growers will able to grow the oxalis triangularis with ease, if attention is paid to it’s basic care instructions and they’re aware of it’s dormancy period.

Dormancy Period

Like other bulb type plants the shamrock has a dormancy period – which is it’s time for rest. They can go into dormancy after the spring and summer growing season which is noticeable when the leaves stop opening in daylight and it begins to look like it’s lacking vitality (this can also happen at other times whenever your plant chooses). They can also temporarily go into dormancy if temperatures become too warm (above 80°F – 27°C) or it’s lacking water and the soil becomes dry for a long period.

If the foliage begins to look withered and die off, stop watering and feeding and let the foliage die down. Once the foliage becomes brown you can remove it and await the next growing period, which could be anything from 2 – 4 weeks. Once you see new growth, normal watering and feeding instructions can be provided.

With its stunning and eye-catching purple foliage, Oxalis triangularis or Purple Shamrock is sure to be the star of the show wherever placed indoors. Provided the proper indoor growing conditions, it will provide you with robust growth and color throughout the seasons. Below is a quick summary of its care.

Oxalis Triangularis care summary: To keep your Purple Shamrock plant healthy, grow in rich, well-drained potting mix and water when the top inch of soil becomes dry. Maintain moderate humidity, fertilize every two to three weeks, situate in bright light and keep indoor temperature between 60°F to 75°F.

Continue reading because we have taken all the mystery out of growing and caring for Purple Shamrocks indoors and having healthy plants showcasing their purple glory.

How To Care For Oxalis Triangularis

Purple Shamrock owns its name triangularis due to the triangle shaped leaves in a deep purple, with a lighter purplish-rose feature in their center. Although the robustly colored leaves are the stars of the show, the plant also produces small, trumpet-shaped flowers in spring in colors of pink or white. The blooms last for several weeks. Another feature of the leaves is they open during the daytime hours and close in the evening.

Those living in mild climates can grow Oxalis Triangularis year-round outdoors as a ground cover. If your conditions are too cold in winter, you can dig the bulbs and store until spring’s warm temperatures arrive again. Plants average around 12 inches tall at maturity.

Purple Shamrock is sure to be an indoor feature and grab the eye’s attention whether grown alone in a container or part of a mixed container garden. It is quite attractive when mixed with plants with silver or white foliage like Dusty Miller or Spider Plant.

In fact, the Royal Horticultural Society has awarded Purple Shamrock the Award of Garden Merit. When properly cared for, Purple Shamrock will grace your indoor space with their outstanding color for years to come.

Why Is Oxalis Triangularis Called False Shamrock?

Another common name for Oxalis triangularis is False Shamrock, because many times it’s commercially marketed as a true shamrock or clover (Trifolium spp.), native to Ireland.

This is due to Purple Shamrock’s three petals and similar looks to that of clover. Actually, it is a member of the wood sorrel family and is a Brazilian native.

Some of the major differences between the Purple Shamrock and true shamrocks is it is better adapted to indoor growing conditions, as the conditions aren’t bright enough for clovers to grow properly. In addition, true shamrocks have a fibrous root system, whereas Purple Shamrock and most species of Oxalis have a bulb-like or tuberous root system.

Another major difference is true shamrocks perform as annuals and the Purple Shamrock is a perennial, although it usually goes through a period of dormancy about once per year.

Oxalis Triangularis (This plant is only five weeks old, but already looks amazing).

Soil Conditions For Oxalis Triangularis

Oxalis triangularis performs well when grown in standard potting mixes that drain well. The bulbs or fibrous roots will rot if planted in soils that are too heavy and retain too much water.

For the best results, use a rich, lightweight potting mix with or without the addition of a slow-release fertilizer. The addition of a fertilizer into the potting mix only means you will not have to worry about fertilizing as frequently as you would with mixes lacking the addition of the fertilizer.

Many types of potting soil are too heavy and don’t drain properly, which can lead to problems with rot. However, if that is what you have on hand you can lighten the mixture before planting your Purple Shamrock. Some soil mixture suggestions include:

  • Mix one part potting soil with one part potting mix
  • Mix one part potting soil with one part peat
  • Mix one part potting soil, one part potting mix, one part peat

Whatever mixture you decide to use to grow your Purple Shamrock, the biggest thing to remember is the soil needs to drain properly and not retain too much water. If after you water you notice the water remains on top of the soil, draining slowly, the mixture is too heavy and needs to be lightened.

Oxalis Triangularis planted in a light potting mix with added vermiculite to improve drainage.

Light Conditions For Oxalis Triangularis Plants

For the best growth, place your Purple Shamrock in an indoor location that receives bright light. If indoor light conditions are too low, the plant’s growth won’t be as robust and it will have a tendency to become leggy.

If you notice this becoming a problem with your Purple Shamrock, just move it to a brighter location. If you desire to give your plant a break from indoor growth, place it in a partially sunny outdoor location and not in full sun. Although it grows best in a bright location indoors, the window reduces some of the sun’s rays and if the location outdoors is too sunny, the leaves can burn.

Indoor Temperature Requirements

The prime indoor temperatures that produce the best growth for Purple Shamrocks are between 60°F to 75°F. When temperatures inside the home become too hot, the foliage will wilt. During winter when conditions inside the home can be warmer due to artificial heating, make sure the plant is not sitting next to a heating vent.

How Often To Water Oxalis Triangularis

Your Purple Shamrock will be more forgiving if you forget to water than if you water too much, which leads to soggy soil conditions and problems with rot. Constantly wet conditions can end up killing your plant, so it’s imperative to water properly.

  • During the growing seasons of spring through summer, water when the top inch of soil feels dry.
  • During the dormant season of fall and winter, water about every two to three weeks.

It is easy to check if your Purple Shamrock needs water by sticking your finger into the soil. If the top inch or so feels dry to the touch, apply water until it runs from the pot’s bottom drain holes.

During the dormant season, the plant has suspended its growing so it does not require the amount of water it needs while actively growing. When watering, use room temperature water and not water that is too cold.

For more tips on how to assess when your houseplants need water, see this article

Although the foliage of Oxalis triangularis is generally considered to be the star attraction, the flowers are also beautiful

Humidity Requirements

When it comes to proper humidity levels for Purple Shamrock to grow properly, it is not as fussy as many indoor plants. Average humidity levels inside the home are usually adequate.

If the air in your home is particularly dry, here are a few great ways to improve humidity easily.

Oxalis Triangularis Fertilizer Needs

Like watering, you only have to worry about feeding your Purple Shamrock while it is actively growing in spring through summer. Stop feeding in fall and winter when the plant goes into dormancy.

If your potting mix contained a slow-release fertilizer, which continues to feed the Purple Shamrock for up to three months, you won’t have to worry about additional feedings for several months. If you choose to continue feeding using a slow-release blend, scatter the granules over the soil and water in well after applying.

Otherwise, use a water-soluble blend for houseplants applied when you water. To keep your Purple Shamrock looking and growing its best, fertilize every two to three weeks.

Salts can buildup in the soil after continued fertilizer applications, which can result in burned foliage so the soil requires periodic flushing. Take your container to the sink and allow water to run slowly through the soil for about five minutes.

This should remove the unwanted salts from the soil. Once the container drains, move it back to its indoor location. You will probably only have to flush the soil of the unwanted salts about every four to six months.

Pruning Requirements

Other than to pinch off any dead foliage, especially as the plant goes into dormancy, the pruning requirements for Purple Shamrocks are low to none.

Care Through Dormancy

Do not be surprised if you start noticing the leaves on your Purple Shamrock starting to brown and become dry after several months of growing strongly. This is the plant entering a period of dormancy, which normally happens in summer, and is a chance for the corms to rest and recharge before another period of growth.

Dormancy can be a little unpredictable indoors, and sometimes the plant will have several cycles of strong growth, followed by die back during the year. Dormancy can also be triggered by temperatures higher than 80°F (27°C).

When the foliage starts to turn brown and die back, cut back on watering and allow the affected leaves to dry out, before pruning them off. Move your plant to an area that is cool and dark for 2-4 weeks to allow the plant to rest.

After this, move the pot back to a brighter location. Commence normal watering and fertilize the plant to stimulate new growth and your plant should bounce back stronger than ever.

How To Plant Oxalis Triangularis Bulbs

Purple Shamrock (Oxalis triangularis) bulb just starting to sprout.

I planted three new pots of Oxalis triangulasis bulbs this spring and the process couldn’t be simpler. It only took a few weeks to go from the bulb pictured above, to the full grown plant you saw at the top of this article.

Major tips to remember when potting your Purple Shamrock are:

  • Any type of container works well, just be sure the container has bottom drain holes to prevent problems with rot.
  • Use a lightweight potting mix that drains well.

Potting steps:

  1. Fill a draining container about three-quarters full of a well-drained potting mix. Water the soil to settle it.
  2. Place the Purple Shamrock bulbs on top of the soil, spacing several inches apart. I planted three bulbs in the pot in the picture below.
  3. Cover the bulbs with soil so they are planted about 1 to 1.5 inches deep. Water the container’s soil again and until it runs out the bottom of the pot.
  4. Place the container is a bright indoor location and you should see new growth appear in around 2-3 weeks. I actually saw growth within a week, but my bulbs were already sprouting when I potted them.
  5. Make sure to keep the potting mix moist while the bulbs are sprouting, then reduce the watering to when the top inch of potting mix is dry. Err on the side of under watering, as root rot is one of the only major problems with this plant.

Repotting Oxalis Triangularis

The plant only requires repotting every few years to add fresh soil or to create new plants from the additional offsets produced. Move up to a container that is one size larger if you aren’t separating the offsets and are just refreshing the soil.

The best time to repot is in winter during the plant’s dormant stage. Just follow the same instructions as for planting new bulbs.

Propagating New Plants

Oxalis triangularis is propagated by separating the offsets to create additional plants. This is best done while the shamrock is in its dormant stage. Remove the Purple Shamrock from its container and gently pull the bulbs apart. Once separated, you can plant the bulbs in new containers.

Before you consider repotting or separating offsets, make sure to allow the foliage to die naturally and don’t trim it off too soon and while it still has color. The bulbs are still gathering nutrients from the foliage and cutting it off too soon can lead to weaker bulbs that don’t perform as well when replanted.

A healthy Purple Shamrock plant 3 weeks after planting.

I’ve also recorded a video about my experience growing Oxalis triangularis and discussing the care needs of this fantastic plant. Check it out below.

Disease Problems

For the most part, Purple Shamrock plants are relatively free of serious disease problems. However, overwatering or growing it in too soggy conditions can cause problems with rot.

When rot is the problem, the underground bulbs turn black and mushy and the entire plant eventually collapses and dies. When this happens, it’s best to just discard the plant and start with a fresh one, watering when the top inch of soil becomes dry and being sure to grow the shamrock in soil that drains well.

The other two problems that can affect Purple Shamrock plants are the fungal diseases powdery mildew and rust. These problems usually occur when temperatures are cool, there is too much humidity and the plant isn’t getting adequate light. Both problems are easy to identify.

  • Powdery Mildew: Powdery mildew shows up on the plant as powdery white patches that affect all portions of the shamrock including the blooms. In severe cases, the powdery substance can coat the entire plant.
  • Rust: Rust shows up as small, light yellow flecks on the foliage, as well as a white powdery substance covering all portions of the plant.

Most of the time these problems aren’t severe and rarely require treatment, other than moving the plant to a bit warmer and brighter location, if possible and decreasing the amount of humidity. However, if the problem is growing you can spray the Purple Shamrock with a fungicide, repeating as suggested on the product label.

Pest Problems

When it comes to possible pests on your indoor Purple Shamrock, the two biggest threats are spider mites and mealybugs. In severe cases of infestation and if left untreated, both pests can kill your Purple Shamrock plant, as well as spread to your other houseplants, so quick treatment is advised. Identifying both pests is easy.

  • Mealybugs: Mealybugs show up on the Purple Shamrock as masses of a white cottony substance, which are actually groups of the pests. They suck out the plant’s juices and can weaken or kill it.
  • Spider Mites: Spider mites are tiny, sap-sucking insects that spin a fine webbing over the Purple Shamrock. Like mealybugs, an untreated infestation can weaken or kill the plant.

Treat both pests by spraying both sides of the foliage and all other areas of the Purple Shamrock with an insecticidal soap or neem. Repeat the treatment as directed on the product’s label.

Why Are My Purple Shamrock’s Leaves Turning Yellow?

If your Purple Shamrock’s foliage starts yellowing it usually means you are giving the plant too much water. This can be caused by watering too often, growing in soil that doesn’t drain well or you’ve planted in a container that doesn’t have bottom drain holes.

If the soil and container are not the problem, then reduce the frequency of your water applications. During the growing seasons of spring through summer, water when the top inch of soil becomes dry, which will probably be once each week. However, when the Purple Shamrock is dormant in fall and winter cut back watering to about once every two to three weeks.

If you are watering correctly, check the pot for a drain hole and if needed, repot into a proper draining container and use a rich soil blend that drains well.

What Causes White Spots On My Purple Shamrock’s Leaves?

If your Purple Shamrock develops white spots on its leaves, this is generally a sign of two fungal problems powdery mildew or rust. If rust is the problem, there is the addition of tiny light yellow flecks on the leaves too.

Both problems are caused by conditions that are too dark, too cool and there’s too much humidity. You can move the plant to brighter and warmer conditions, as well as cut down on the humidity. In addition, you can spray the entire plant with a fungicide to control the problem.

How Can I Propagate New Oxalis Triangularis Plants?

While the Purple Shamrock is dormant in fall and winter, gently remove it from its container and carefully separate the bulbs. Plant the bulbs in a new container, making sure it has bottom drainage and into a well-drained soil. Space multiple bulbs several inches apart and plant about 1.5 inches deep in the soil.

Is Oxalis Triangularis Toxic To Cats?

The leaves of Purple Shamrock have a bitter taste, which usually prevents cats and dogs from having more than a small taste, however, they contain oxalic acid, which is toxic when large quantities are consumed.

Do Purple Shamrock Leaves Close At Night?

Like the majority of Oxalis types, the leaves of Purple Shamrock close at night and reopen during the daytime hours.

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