Grow and Care for a Scotch Broom Plant

Grow Scotch broom in full sun, in poor soil that drains, and skip fertilizer. Scotch broom is Cytisus. Check your county noxious-weed list before you plant Cytisus scoparius, including Moonlight.

Give it full sun, lean soil that drains, and skip fertilizer

Scotch broom wants full sun and poor soil that still drains. Extra water and fertilizer shorten its life. [1] It also takes dry ground and coastal salt once the roots are down. [2] Water a new plant through the first year, then let rainfall carry it except in a long dry spell. Warminster broom is the earlier garden hybrid. Moonlight is still Cytisus scoparius — check the list before you plant it. When the flowers fade, see Prune Scotch Broom.

Plant a young pot at the same depth, in spring or fall

Set a young container plant so the top of the root ball sits even with the surrounding soil. Plant in spring or fall, when you can water and the heat is not extreme. [3] A large, field-dug shrub sulks; buy a pot you can slide out without tearing the roots.

1. Soak the pot, then dig a hole as deep as the root ball and two to three times as wide. Tease circling roots.
2. Set the top of the root ball at the surrounding soil grade. Do not bury the stems under extra backfill.
3. Leave about five to eight feet for a mature shrub. Read the size on the tag before you dig.
4. Backfill with the original soil, water to settle, and mulch the root zone. Keep bark a few inches off the stems.

Moonlight uses that same depth. Warminster broom uses that same depth too; it only needs a little less room to the sides.

Root a summer cutting if you want another plant

Named garden brooms root from a summer shoot. Do not sow Cytisus scoparius seed where the species is a noxious weed; pods throw seed several feet, and that seed can sit in the soil for years.

1. After bloom, take a semi-ripe green shoot about four to six inches long.
2. Strip the lower leaves, dip the cut in rooting hormone, and stick it in a sandy mix that drains.
3. Keep the mix barely moist under a cover or mist until roots take. Do not sit the cutting in standing water.

Not Genista, Spanish broom, or gorse

Scotch broom is Cytisus, a pea-family shrub with green ridged stems and yellow or cream pea flowers. Other plants share the word broom and they are not this one. [4]

• Scotch broom (Cytisus scoparius) — five-angled green stems; trifoliate leaves on the lower shoots; flowers in the leaf axils. ‘Moonlight’ is still this species.
• Warminster broom (Cytisus × praecox) — a smaller, earlier hybrid with mostly simple leaves. The shop tag may still say Scotch broom.
• Genista — another pea-family broom, often greener on alkaline ground. It is not this genus — see How to Grow Genista.
• Spanish broom — Spartium junceum, with round stems and flowers in clusters at the tips, not in the leaf axils.

Gorse is Ulex, with sharp spines. Butcher's broom is Ruscus, a different evergreen with red berries. A witches' broom is a dense, witchy cluster of shoots on a tree, not a shrub you buy. Desert broom is Baccharis — see How to Grow Coyote Brush if that is the tag. If the stems are green and ridged, the flowers are pea shaped, and the Latin starts with Cytisus, you still have this plant.

If a young plant flags in a dry week, soak the root zone once, then check a few inches down before you water again.