Old-fashioned shrubs need love, too. Lilacs and bridal-wreath spireas have been around for a century, but neither are native to the Americas. Spirea and some lilacs are natives of China. Lilacs are members of the Oleaceae (olive) family, and native to eastern Europe as well as Asian countries. Early European immigrants brought saplings of lilacs to America. Both shrub varieties are tolerant of low water and alkaline soil, extensive pruning, and heat or cold.
Bridal wreath spirea grows in a graceful arching habit, while lilacs grow upright, but both spread sideways. Their tolerance of extensive pruning means that deer can safely munch away without destroying the shrubs.
They grow in full sun, and attract butterflies and tiny insects since they have shallow sources of nectar. Spirea is a member of the enormous Rosaceae family, botanic name is Spiraea prunifolia. It tolerates light shade, and blooms in early spring, the blossoms being neat clusters of tiny white flowers. Pruning to shape is best done immediately after flowering, but can be pruned at any time without risking the life of the shrub.
Bridal wreath spirea, although susceptible to the same diseases that afflict other members of the Rosaceae family such as fire blight, powdery mildew, aphids, scale, root rot, leaf spot and leaf roller, is seldom damaged by any of those problems in our area.
Lilacs have long been treasured for their exhilarating fragrance, even though most just bloom in early spring. Breeders have worked on them to encourage added blooming, producing some known as “Bloomerang,” for instance.
The botanic name for lilac is Syringa vulgaris. Lest newcomers think this is the Idaho state flower, it is not. The Idaho state flower is popularly known as Syringa, but its botanic name is Philadelphus lewisii (yes, the Lewis of Lewis and Clark early 19th century exploration). It’s also called “mock orange” for the orange blossom-like aroma of its flowers.
Breeders have worked on lilacs extensively, producing shrubs with various limits of growth. Both lilacs and bridal wreath spirea are deciduous, but may be used as a hedge, either by themselves or in combination with the other. Keep in mind lilacs will need full sun for blooming.
Some extended blooming can occur if you have room to plant early hyacinth lilacs, then Chinese and Persian varieties, and late-spring Japanese, Hungarian and Preston tree lilacs. Those bred to yield a second bloom are not as floriferous as the early bloomers.
Lilacs in our area are pretty free of insect problems, although some cosmetic damage to leaves may occur by edge notching by black vine weevils. It it’s severe, their larvae may be damaging the shrub’s roots. The main problem our lilacs face is late summer powdery mildew. It doesn’t appear to threaten the life of the shrub, but isn’t attractive.
Send garden questions to firstname.lastname@example.org or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.
Boise has inexpensive organic mulch
Organic mulches can prevent weed germination, keep soil cool on hot days and retain soil moisture, then as they decay they add organic matter to the soil. Boise Forestry again has a good supply of chips from trees for $15 per cubic yard. They load, usually twice each day, but call 608-7700 for times or see www.cityofboise.org/parks/forestry.