Long-lasting sweet-smelling blooms, drought-tolerant, pest-free, low-maintenance... it all sounds a little too good to be true. But if you're looking for an easy, beautiful plant for your garden, consider the genista, or rock broom.
Genista, AKA Rock Broom
Genista, also known as rock broom or broom plant, is a short, shrubby blooming plant that is perfect for those dry, hot areas of your garden. Genista usually has small yellow blossoms that are similar in form to those of sweet pea flowers, which makes sense, since genista is a member of the legume family. It's very low-maintenance, though it has a reputation for being invasive in certain areas.
Genista usually blooms in late spring or early summer, and the blooms are highly fragrant and sweetly scented, reminiscent of sweet peas. Bees and other pollinators love them as well.
Genista should be planted in spring or fall in a spot that receives full sun. Rock brooms aren't picky about soil and in fact grow perfectly happily in lean, sandy, or even gravelly soil. The only soil they'll struggle in is wet, heavy soil.
- To plant genista, plant a hole as deep as the root ball of the plant and twice as wide.
- Position your plant so that it's straight and so that you're happy with how it looks.
- Backfill the hole with soil, firming it gently to help eliminate air pockets.
- Water the genista, then apply a layer of mulch.
Growing Rock Broom in Your Garden
If rock broom has a spot in full sun and loamy or sandy soil, there really isn't much maintenance you'll have to do. During its first year in the garden, you'll want to make sure rock broom plants get an inch of water per week, either via rain or from the hose. If at all possible, let the soil dry out between waterings. After the first year, it shouldn't need much in the way of watering unless your area experiences prolonged drought conditions.
Genista doesn't need to be fertilized. It grows perfectly well even in lean, infertile soils.
To prevent it from re-seeding, you might want to deadhead when it's finished blooming, but other than that, the only pruning you'll need to do is to remove dead stems or branches and do any shaping required to keep it looking the way you want it to.
Rock Broom Pests and Problems
Rock broom doesn't have many pest or disease issues. The only pest that seems to attack genista plants is the web worm, and those can be removed by hand-picking or by cutting off branches that have the webs on them.
Is Genista Invasive?
Some varieties of genista are considered invasive in certain areas, such as French broom (Genista monspessulana), which is labelled as a noxious weed in California and Australia. However, many of the most popular varieties are not invasive, and these are the ones you're most likely to find in nurseries and plant catalogs.
Is Genista Toxic?
Genista can be toxic to dogs, cats, and horses. It contains toxic alkaloids that can affect the central nervous system and heart if it's eaten in large quantities. While this makes it unattractive to deer and rabbits, it also makes it unsafe to plant in an area where pets spend a lot of time, especially if your pet has a tendency to chew on your plants.
Popular Rock Broom Varieties for Your Garden
While there are dozens of varieties of genista, some are definitely easier to find and more preferred than others. The varieties of rock broom below are readily available, non-invasive, and beautiful.
Creeping Broom (Genista pilosa)
Creeping broom, true to its name, grows to around one foot tall and three feet wide. Its sunny yellow flowers last all summer long, and it thrives in dry, sunny areas. It makes a perfect groundcover and is an ideal rock garden plant. This variety also looks wonderful planted in stone troughs or planters, where it can spill over the sides. Creeping broom is hardy in Zones 5 through 7.
Dyer's Broom (Genista tinctoria)
Hardy in Zones 4 through 7, this is another rock broom variety that grows well even in northern gardens. It grows to two feet tall and wide, and usually blooms in June. This variety is considered invasive in certain areas of the U.S. and Canada due to how easily it spreads via seed. Its name comes from the fact that a yellow dye can be created from the flowers and young stems of the plant, making this an interesting option for gardeners who are also interested in fiber arts.
Lydian Broom (Genista lydia)
The Lydia broom plant forms a low-growing, spreading shrub that grows up to 18 inches tall and 36 inches wide. When in bloom, which happens in late spring through early summer, Lydia genista is absolutely loaded with small, yellow, fragrant flowers. Like other genistas, Lydia is drought-tolerant and low-maintenance. This is a good option for gardeners in slightly cooler areas, as Lydian broom is hardy to Zone 6.
Mt. Etna Broom (Genista aetnensis)
Mt. Etna broom grows into a small, 12 to 16 foot tall tree which produces plenty of sweetly-scented yellow flowers. It's very drought-tolerant and low-maintenance, and it works well underplanted with other annuals and perennials that do well in sunny, dry conditions. Mt. Etna broom plant is hardy in Zones 7 through 10.
Spanish Broom (Genista hispanica)
Also known as Spanish gorse or Spanish furze, Genista hispanica is a short (30 inch) tall, spreading shrub with a somewhat spiny appearance. Like other genista varieties, Spanish broom produces masses of bright yellow, fragrant flowers in late spring. If you live in a cold climate, this is the best option for you, since Spanish broom is hardy to Zone 4. Spanish broom can spread up to five feet, making this an excellent groundcover, especially for areas that are hot and dry, or don't have easy access to irrigation.
What to Plant With Rock Broom
Catmint, weigela, lavender, thyme, Russian sage, yarrow and poppies all make excellent companions for genista. In fact, many Mediterranean herbs, such as oregano, rosemary, basil, and tarragon appreciate the conditions in which genista thrives, and all would make excellent companion plants.
Relax and Enjoy
Genista is one of the most undemanding plants you can grow in your garden. Not only is it drought-tolerant, but it requires almost no maintenance. Enjoy its sweetly-scented blooms all summer long, and know that your local pollinators are enjoying it as well!