lilac (Syringa vulgaris) photo by Schoeband

I have a lilac in front of my house in a west-facing planter. It is of the `California Rose’ variety and was purchased a few years ago. It bloomed this spring but is blooming again now. I have two other lilacs that are not blooming again, but I also have a hydrangea that has a bloom on it. When I cut my hydrangeas back I missed a small branch near the base of one plant and that branch now has a small bloom on it. I am not complaining about the blooms out of season but I wonder what causes this phenomenon.
Nadine Wilson, Castaic
Lilacs, known for their heavy fragrances and rich, hyacinth-like inflorescences in pink, lilac or blue, will occasionally rebloom in the late fall or early winter, especially those types such as `California Rose’ that grow in warm winter climates such as ours. If you pruned your lilac and removed fresh or faded flowers soon after they bloomed last spring, that could explain the reblooming you are seeing now.
Faded flowers that are not removed from lilacs, or any other plant, go to seed. Seed development is the most energy-demanding physiological process and probably would have inhibited your current flower production. But if last spring’s flowers were removed before going to seed, this would have allowed the plant’s resources to be channeled into the flower production that you witness today.
`California Rose’ is one of a number of lilac cultivars that were hybridized from the lilacs growing at Descanso Gardens in La Canada Flintridge. Unlike most lilac (Syringa) cultivars, Descanso hybrids do not require much winter chill in order to bloom in the late winter or early spring. `California Rose’ is a widely grown cultivar that, if not in stock, should be available by special order from most nurseries in our area.
If you visit Descanso, make sure you take a look at the lilac collection there. People associate the Descanso Gardens with the rapturous camellia forest growing there under native oaks, but the lilacs, easily missed because they are off the beaten track of the casual visitor, should not be overlooked. To appreciate the Descanso lilacs in full bloom, plan a visit for March or April.
Lilacs are known for their longevity, easily living 100 years or more. A primary reason for their staying power is their strong suckering tendency. New growth is constantly pushing up from the soil, which makes propagation easy.
You can create new plants simply by digging up young suckers along with their roots and transplanting them to other parts of the garden. Before conducting this procedure, make sure that the lilac you want to propagate is growing on its own roots. If you have a grafted plant, the suckers will develop into lilacs whose characteristics may disappoint you. In such cases, suckers should be regularly dug up and discarded instead of propagated.
Lilacs may be grown into magnificent hedges 5 to 15 feet tall, depending on variety. Few people, however, take this horticultural plunge since lilacs are deciduous and do not bloom for more than a few weeks in the spring.
In addition, they can be burnt in our hot summers and should be given good ambient light without direct exposure to southern or western sun. Too much shade, however, will result in mildewy leaves. Lilacs require fast-draining soil to grow well.
As for hydrangeas, they may bloom right through December, as long as the weather remains fairly mild, as it has this year. The fact that you pruned most of your plant only to see a new flower growing at its base tells you that the plant’s energy is being diverted into the sole unpruned branch.
In general, lower branches flower the most due to the hormonal balance at work in them. In fruit trees, lower branches are the most fruitful due to their more horizontal orientation, which favors flower development and fruit growth.
Tip of the week
Lilac flowers lose their freshness after only three to five days, so extra care is required to maintain them in a vase. Maximize the longevity of any cut flower by changing the water daily and adding a floral preservative. You can make your own flower preserving formula by mixing 1teaspoon bleach, 1 teaspoon sugar and 2 teaspoons lemon juice in one quart of lukewarm water.
As soon as cut flowers are removed from the plant, they should be placed in the prepared water. Ideally, an inch or two is cut off the bottom of the floral stems, underwater, at a 45 degree angle. Leaves that would be underwater should be removed.