Unlike the old favorites that need cold winters to bloom, these newer varieties thrive without winter chill

Lauren Bonar Swezey,  – June 22, 2006

Flowers as pretty as party dresses, with a gently sweet fragrance reminiscent of Grandma’s dressing table, make lilacs sentimental favorites. In a world that swirls around us too fast, lilacs spark nostalgia ― possibly for a place where they once flourished, or perhaps for another era.

But this nostalgia isn’t easy to create everywhere. In mild-winter climates, you can’t pop just any lilac ( Syringa vulgaris) into the ground and expect an exuberant show of blooms come midspring. You’ll need to buy low-chill varieties.

Why? Because most lilacs prefer the kind of winter chill that sends us scrambling for heavy wool coats. Not so the low-chill varieties.

The first low-chill lilac, called ‘Lavender Lady’, was developed in Southern California 30 years ago by Walter Lammerts, a researcher and hybridizer with Rancho del Descanso ― a former wholesale nursery that’s now the site of Descanso Gardens, a botanical garden open to the public. “Walter was an excellent hybridizer,” says Bob Boddy, son of the nursery’s owner. “He came up with a progeny of 350 potentially outstanding low-chill lilacs.” Although many varieties of lilacs are sometimes attributed to Lammerts, ‘Lavender Lady’ and ‘Angel White’ were his only direct creations.

But other descendants from the original plantings have been introduced through the years by Descanso’s staff. The lilacs ― often referred to as Descanso Hybrids ― now number a dozen or so, and many of them can still be seen growing at the gardens (1418 Descanso Dr., La Cañada Flintridge; 818/952-4400).

How to grow the best flowers

Like roses, lilacs are a bit greedy. To produce an abundant crop of flowers, they need plenty of sun. They also need space; crowding reduces air circulation and makes them more prone to powdery mildew. In mild Southern California, avoid planting them near lawns; year-round watering can prohibit dormancy and flowering.

Unlike many plants that thrive in rainy Eastern climates, lilacs prefer the arid West’s alkaline soil. It’s generally not necessary to add soil amendments at planting time unless the soil is very sandy or heavy clay.

After planting and until plants are established, water regularly to keep the soil moist but not soggy. In Southern California, after the third season of growth, hold off watering starting in late September to induce winter dormancy (colder winter temperatures throughout most of Northern California induce dormancy naturally, so it’s not necessary to cut off water). If winter rains are sporadic, begin watering again when the buds start to swell (around late February).

Fertilize lilacs in late winter with an organic fertilizer such as blood and bone meal, or with a commercial product.

After lilacs bloom, remove the spent flowers where the leaves join the stems just above the points where next year’s flowers are forming; leaving spent flowers on the plants can inhibit next year’s bloom. Don’t prune lilacs heavily (or later than June) or you’ll cut off developing flower buds. To control growth and shape the plants, pinch back new shoots.

Eight lilacs for mild-winter climates

Low-chill lilacs can be purchased at many nurseries. If you can’t find the variety you want, ask your nursery to order it from L. E. Cooke Co. in Visalia, California (wholesale only).

Descanso Hybrids
• ‘Angel White’: Mildly fragrant white flowers develop on the upper branches of a thick, bushy shrub that grows 8 to 10 feet tall. Selected and introduced from Lammerts’ original plants by Monrovia Nursery. “The idea was to name it after the baseball team and call it ‘Los Angeles Angels’,” says Boddy. But it didn’t get registered that way.

• ‘California Rose’: Mildly fragrant medium pink flowers appear in profusion on a vigorous shrub that grows 8 to 10 feet tall.

• ‘Lavender Lady’: Lavender flowers with good fragrance develop on a shrub about 8 to 10 feet tall. ‘F. K. Smith’ and ‘Sylvan Beauty’ are similar, but the flowers on ‘F. K. Smith’ are a bit lighter on an 8- to 10-foot-tall plant, and ‘Sylvan Beauty’ has pinker, more open blooms on a 10- to 12-foot-tall plant.

Other low-chill lilacs
• ‘Blue Skies’: Very fragrant lavender flowers appear on an 8-foot-tall plant. Heavy bloomer. No need to adjust water to induce dormancy. Developed by rose hybridizer Ralph Moore in Visalia, California.

• ‘Esther Staley’ (Syringa hyacinthiflora): Very showy, pure pink flowers with good fragrance develop on rounded shrubs that grow to about 8 feet tall.

• ‘Excel’ (S. hyacinthiflora): Light lavender flowers with good fragrance appear on rounded shrubs 8 feet or taller. Massive bloomer. Blooms earlier than the others listed (late February or early March).