- Information On Broom Shrubs: Controlling Broom Shrubs In The Landscape
- About Broom Shrub Plants
- Where Do Broom Shrubs Grow?
- Controlling Broom Shrubs with Chemicals
- Sweet Broom Shrub Care – How To Plant Broom Shrubs
- Sweet Broom Info
- How to Plant Broom Shrubs
- Broom Shrub Care
- Planting French broom
- Pruning and caring for French broom
- Learn more about French broom
- Smart tip about French broom
- Scotch Broom Pruning: When And How To Trim A Scotch Broom Plant
- Scotch Broom Pruning
- How to Trim a Scotch Broom
- What Age to Prune a Scotch Broom Plant?
- Exotic Species: Scotch Broom
Information On Broom Shrubs: Controlling Broom Shrubs In The Landscape
Broom plants, such as Scotch broom (Cytisus scoparius), are common sights along highways, in meadows and in disturbed areas. Most broom shrub varieties were originally introduced as ornamentals but some species became useful as erosion control. Broom shrub plants may get 9 feet tall and produce some spectacular bloom displays in spring. The plant can get a bit invasive in some areas though, but a little information on broom shrubs will help you control the plants while still enjoying their ease of care and brilliant blooms.
About Broom Shrub Plants
Brooms form small to large shrubs that grow very quickly. The plants have become quite invasive with seeds spreading and sprouting quickly. This speedy development makes the plants a threat to native species. Brooms produce wide branching root systems and thick tenacious stems. The stems die back in dry weather and produce flammable “torches” of plant material. There are several broom shrub varieties but the most common
are the Scotch and Spanish, which were introduced as erosion control.
Brooms can get 3 to 10 feet tall with angled stems and small simple to trifoliate leaves. Stem shape separates the broom shrub varieties. Scotch broom has a five-sided stem while French and Portuguese have 8 and 10 angled stems. Spanish broom is so closely angled that it appears almost round. The bright yellow flowers have a pea-pod like appearance which yield to black or brown pods filled with dark green seeds in late summer.
Where Do Broom Shrubs Grow?
Rather than ask, where do broom shrubs grow, you should ask, where don’t they grow. The only space that is not pleasing to broom shrubs is a soggy, boggy and shady location. They establish quickly in disturbed areas but also in grassland and forests. Their adaptability and rapid growth can lead to an invasive tendency in some areas.
Controlling broom shrubs with mechanical pulling and cultural management can help in areas with low infestations. This can be difficult on plants like Scotch broom, which may have a 6-foot long taproot. Chop out the plant in spring when the soil is moist and has some give. You can also cut the green foliage and let the stems dry out. Then follow with controlled burning to prevent the plant from re-sprouting.
Controlling Broom Shrubs with Chemicals
Instead of burning, you can paint stumps with a systemic herbicide. You can also apply a foliar spray, which will translocate through the stoma in the leaves, down into the vascular and root system of the plant. The best time to spray is between April to July when leaves are dry and temperatures are 60 to 80 degrees Fahrenheit (15 to 26 C.).
Note: Chemical control should only be used as a last resort, as organic approaches are safer and much more environmentally friendly.
Sweet Broom Shrub Care – How To Plant Broom Shrubs
There are over 30 species of Cytisus, or broom plants, found in Europe, Asia and northern Africa. One of the more common, sweet broom (Cytisus racemosus syn. Genista racemosa) is a familiar sight along highways and in disturbed areas of the west. While many people consider the plant a noxious weed, it is an attractive plant with its pea-like golden yellow blooms and bright green compound leaves. The plant grows quickly and produces a nice airy bush with drought and cold tolerance. In the proper space, growing sweet broom shrub will add a nice wild touch to the landscape and enhance the area with its scented blossoms.
Sweet Broom Info
A common bit of sweet broom info is its relation to the pea family or Fabaceae. This is evident in its bloom form and also means the plant has the capacity to fix nitrogen in soil. The plant was popular for its rapid growth and low sweet broom shrub care. But is sweet broom invasive? It was used by the United States transportation department to colonize disturbed roadsides after building trans-continental roads and to enhance soil properties but is now considered invasive in some regions.
the plant can become invasive, why then would you want to know how to plant broom shrubs? Besides sweet broom’s nitrogen fixing abilities and its rapid growth with fibrous soil stabilizing roots, the sweet smelling, attractive blooms are a harbinger of summer. Across many of the nation’s highways it blazes with color and attracts pollinators of many species.
With careful management, sweet broom can be a wonderful addition to the landscape. The plant forms a shrub 6 to 8 feet wide with a slightly smaller spread. If established in well-drained soil, the plant’s needs are met with low fertility additions and moisture. Pruning broom shrubs is optional but can help to keep it in the habit you wish. This low maintenance plant may be just the thing for an easy care garden.
How to Plant Broom Shrubs
Select a bed where the soil has been worked deeply and is freely draining. These plants tolerate a range of unpleasant conditions such as windy sites, low fertility and even rocky areas.
Dig a hole twice as deep and wide as the root ball. Push the soil around the roots and tamp it down. Water your sweet broom regularly for the first few months if rainfall isn’t sufficient to keep the soil moist.
Broom shrubs don’t need supplemental food in most situations but add iron sulfate in spring where soils are alkaline. Try growing sweet broom shrubs in groups as a hedge or border with brilliant yellow flowers and stems of wild abandon.
Broom Shrub Care
Once the flowers are spent and seed heads have formed, pruning broom shrubs is recommended to reduce seed spread. Just a light deadheading will do the job. Other trimming is up to you but not strictly necessary. Trim the plant in late fall, late winter or before flower buds have formed if you want to keep the size down without diminishing blooms.
The biggest pest issue is webworms. These pests overwinter in old debris, so keep the area under the plant raked clean. Use organic mulch to prevent weed competitors and conserve moisture.
The broom family is a hardy, no fuss group that is much maligned but can perform well in the cultivated garden with little care.
French broom is a fantastic shrub with yellow flowers that blooms in spring.
Key French broom facts
Name – Cytisus scoparius
Family – Fabaceae
Type – shrub
Height – 6 ½ feet (2 meters)
Exposure – full sun
Soil – ordinary, rather sandy
Foliage – deciduous
Flowering – April to June
Easy to care for, the planting and pruning contribute towards increasing growth and blooming of French broom.
Planting French broom
If purchased in a container, French broom can equally be planted in fall or spring, as long as it doesn’t freeze.
But as is the case for most shrubs, planting it during the month of November is when you’ll best ensure that it settles in perfectly.
If you must plant your French broom in spring, provide for regular watering over the first summer.
- French broom loves sunbathed locations to bloom well.
- Refer to our guidelines for planting shrubs.
Propagating French broom
Making cuttings is the easiest and fastest method to propagate French broom.
- The best season for cuttings is summer, on wood that hasn’t born flowers yet.
- The ideal substrate is special cutting soil mix.
Pruning and caring for French broom
French broom is a shrub that is easy and only requires very little care, both for pruning and for watering.
It is preferable to not prune it too early after planting, so that it may quickly grow into its natural shape.
In the subsequent years, prune the sprigs of the year on the French broom after the blooming more or less by half.
You can also reshape your French broom to a nice shape just after the blooming.
- All there is to know on pruning shrubs
Watering French broom
As regards watering, the first year is the only year where regular watering is needed.
Learn more about French broom
Its growth is relatively fast and it adapts well to most soil and climate types.
French brooms only live for a few years, 5 at most, which means they must be replaced after this beautiful span of time.
You can also propagate it after 2-3 years by preparing cuttings, which is a great way to replace the mother plant regularly.
Very hardy to freezing and cold, rest assured that it won’t suffer in any way even when temperatures drop to 5°F (-15°C).
The most common French broom varieties are among others:
- Cytisus albus – Cute white flowers in spring.
- Cytisus beanni – Very beautiful intense yellow blooming.
- Cytisus purpureus – Very appealing original purple color.
- Cytisus kewensis – Delicate creamy white blooming.
- Cytisus scoparius – The most common variety, with its distinctive golden yellow color.
Smart tip about French broom
In order to protect roots from the cold in winter, go natural and mulch the foot of the tree with plant-based mulch.
The sprigs collected during the pruning are used to make brooms.
- Setting up a flowered hedge.
Broom’s vivid yellow flowers bring warmth and vibrancy to the garden, as well as a wide range of wildlife. It is commonly found across the UK on sandy pastures and heaths, occasionally in woodland and often near the coast. Broom is also a good shrub to introduce into a home garden, particularly on steep or very dry banks or slopes, where other shrubs may struggle. But broom is lovely in many an informal wildlife garden and not only will it delight the eye, it will also even help other plants grown near it by fixing nitrogen from the air into the soil.
Broom is a deciduous plant. It blooms its vivid yellow in late spring. It prefers to be planted in full sun but will tolerate a little shade and can be used to provide texture and height in a flower border. The site can be exposed or sheltered – in the wild broom is able to colonise the most unlikely looking coastal places. It will grow in any well-drained soil though be warned that it may not thrive on shallow chalk soil. However, it should be okay with very acid soils and can tolerate maritime exposure and atmospheric pollution.
You can grow broom from seed although it is fussy about being transplanted from a fairly young stage so it can sometimes be easier to take a semi-ripe, late-summer cutting from an existing plant. If you want to take a punt you could try planting seeds where they are to grow in late summer or early autumn when they ripen, though germination can be a little hit and miss. With half-ripe cuttings, a cutting planted into a cold frame in August will root in the spring. It is essential that it is not left too long before potting up because it soon becomes rather intolerant of root disturbance, especially when more that 20cm tall.
The broom plants have a root system that delves very deep. One established they are extremely drought tolerant and are hardy down to about -20 degrees Celsius. Its tolerance of pollution means it could be a good plant for a city centre garden as well as for anywhere with difficult soil conditions.
Why grow broom in the garden?
Aside from its beautiful yellow flowers, the main reason to grow broom in the garden is that it has a symbiotic relationship with certain bacteria which form nodules on the plant’s roots and fix atmospheric nitrogen into the soil. Some of this is used by the growing plant itself, but some is also made available to other plants growing nearby and the soil of your garden bed will be naturally and organically enriched.
As a nitrogen fixer, broom is a beneficial companion plant for many other plants. It is also a boon to the bees and several species of caterpillar and butterfly, making it a wonderful addition to a wildlife garden.
Scotch Broom Pruning: When And How To Trim A Scotch Broom Plant
Scotch broom (Cystisus scoparius) is an attractive shrub that rises to about 10 feet (3 m.) high with an open, airy growth pattern. Despite the beauty of its bright yellow spring flowers, it can easily look disheveled if not pruned correctly. Pruning a scotch broom shrub must be done conservatively and at the correct season. Read on for information about scotch broom maintenance.
Scotch Broom Pruning
Scotch broom plants may require pruning because of broken or diseased branches, like any other shrubs. More often, however, gardeners decide to prune a scotch broom plant because it has outgrown its allotted space or grown scraggly as it matures.
However, once the plant is fully grown, it may be too late to reshape it by trimming and it can even get out of hand, requiring control. Scotch broom maintenance must begin while the shrub is young.
How to Trim a Scotch Broom
The first rule for pruning a scotch broom shrub involves timing. Although broken or diseased branches can be pruned off at any time of the year, size or shape pruning should only be undertaken in late spring, immediately after flowering.
This rule about pruning a scotch brook shrub in springtime is critical if you want an attractive bush. The scotch broom sets its buds for the following year just after spring flowering. If you snip in autumn or winter, you will dramatically reduce the number of flowers your plant produces the next summer.
What Age to Prune a Scotch Broom Plant?
It is also important to begin trimming when the tree is young. Begin your scotch broom pruning before the tree is mature, and prune back its stems annually. This stimulates growth to prevent that scraggly look.
But when you prune a scotch broom plant, be conservative about how much to trim. Only trim back a little to shape the tree. Never cut off more than one-quarter of the foliage in any one year. If you need to do more scotch broom pruning than this, spread the clipping over a number of years.
Once the tree has grown large, it is too late to repair its scraggly look. According to experts, the mature branches do not retain many green buds. If you cut these branches back severely, you are not likely to get a fuller plant; in fact, if you prune a scotch broom shrub in this manner, you may kill it.
Renewal pruning is most commonly used for potentially large, fast-growing shrubs such as forsythia, philadelphus (mock orange) and ribes (flowering currant). But it can also be used on weigela, kerria, deutzia, early-summerflowering spiraea, brooms and other shrubs that flower on last year’s shoots, as long as they finish flowering before mid/late July. Don’t use this method for pruning later-flowering shrubs (including roses and hydrangeas, which have their own special pruning requirements), or you’ll ruin the coming season’s flowering.
What to cut off
Renewal pruning is like a slightly extended form of deadheading, done as soon as flowering is completely finished. First, cut out any dead, diseased, spindly or weak shoots. then, starting from the edge of the shrub, take each stem in turn, and trace it down from the cluster of dead flowers at the tip to the junction with the first strong, non-flowered side shoot. Use sharp secateurs to cut the stem off just above this shoot. This may mean removing quite a long piece of stem which looks drastic, but don’t worry – it’s the correct treatment. Continue stem by stem until you have deadheaded the whole shrub. Stack the old stems tidily to one side as you work, so they are well out of your way.
If mature shrubs look congested with lots of overcrowded stems, cut out a few of the thickest and oldest ones as close to the base of the plant as possible. Look carefully before cutting and aim to thin the oldest main stems out, rather than chopping gaping holes that spoil the look of the plant. It’s also a good idea to remove one or two big branches from the centre of the shrub to let in more light and air, rather than taking out easy-to-reach stems round the sides.
Stand back and study the shape of the shrub that’s left. If necessary, shorten some long or projecting stems to leave a neat, tidy and symmetrical shape.
Each spring, mulch and feed spring and early summer-flowering shrubs that need regular hard pruning, to replenish their reserves of nutrients. If you’re feeling generous, also give them a dose of liquid tomato feed in early August to promote bud initiation and better flowering next year, and water well in if the soil is dry.
Exotic Species: Scotch Broom
Scotch broom is a shrub with bright yellow flowers and stiff, slender branches.
© Anne Tanne
- Perennial shrub.
- Strongly angled, green stems.
- Small leaves occur together in groups of three.
- Bright yellow flowers in leaf axils.
- Fruit is a brownish-black pod with hairs only along the seams.
Habitat and Ecology
Scotch broom (Cytisus scoparius) is found along the east and west coasts of North America and in Idaho, Montana, and Utah. Native to northern Africa and parts of Europe, it was first introduced to North America on the east coast and was later introduced to California as an ornamental. From the 1850s through the early 1900s, Scotch broom was frequently planted in gardens. Later, it was used for erosion control along highway cuts and fills.
Scotch broom flourishes in full sunlight in dry, sandy soils, but it can survive under a wide variety of soil conditions. However, it does not tend to survive in very arid or cold areas. Scotch broom invades dry hillsides, pastures, forest clearings, dry scrublands, dry riverbeds, and waterways. Several characteristics contribute to its success as an invasive plant: (1) although it loses its leaves during dry conditions, the photosynthetic tissue in its stems allows it to grow throughout the year; (2) its roots host nitrogen-fixing bacteria, which helps the plant to establish in nutrient-poor soils; and (3) it produces abundant seeds that remain viable in the soil for many years. In addition, Scotch broom is slightly toxic and unpalatable to livestock.