Using its brilliant yellow leaves that hold their color all season, “Goldmound” spirea (Spiraea japonica “Goldmound”) is a deciduous shrub that adds a spot of sunshine wherever you plant it. “Goldmound” grows 2-3 feet tall and up to 4 feet wide in sunlight in U.S. Department of Agriculture plant hardiness zones 4 through 8 and in regions of greater zones where summers are not extreme. The vibrant yellow leaves are topped in late spring from flat clusters of bright pink blossoms that resemble yarrow. As with other late-spring flowering shrubs, harassing “Goldmound” spirea in late winter to early spring before new growth starts.
Wipe the blades of your hand pruners with full-strength household antiseptic cleaner. A family antiseptic cleaner is just as successful as bleach or rubbing alcohol at preventing the transfer of plant disorders from resources, but is less corrosive to metal tools.
Cut all the stems of the “Goldmound” spirea down to over 3 inches of the earth to ensure new, lush growth and several blooms. This may be done annually or every couple of years as the plant starts to look leggy or outgrows its distance. If you prefer to keep the height of the shrub, cut out one third of the oldest stems in the base each winter to prompt new growth.
Deadhead the flowers as they fade in late spring and early summer to prompt a new flush of blooms. Hand-held pruning shears make short work of the endeavor.
Remove any broken, dead or diseased branches at the bottom of the affected stems whenever you find them. Cut at least a few inches into live wood, to 1/4 inch above the following node — a swelling from a stem and a leaf. Make the cut in a 45-degree angle, slanting away from the bud.