Care and Planting of Lilacs

After growing lilacs since 1992, I can only talk about the experience I have had with them. By no way am I an expert, I consider every day a learning experience when it comes to farming. With that said, I can tell you what we do to promote bloom here on our farm.

We have alkaline soil and cold winters which are extremely essential for successful flowering. We live in the high desert which means we get very warm summers. Lilacs require at least six hours of sunlight a day and believe me we get plenty of that here in Acton. Lilacs are deciduous (they lose their leaves in the winter) and to facilitate their dormancy, we start reducing their water intake in September and by Halloween we have altogether stopped watering. Around Halloween or thereafter, we usually receive our first frost and the lilacs drop their leaves for winter.

When we apply fertilizer, it is usually before the first rains of late fall and winter. Too much nitrogen will send the lilacs into a growing mode when they start to break bud, instead of a flowering mode. We use a controlled fertilizer that has a low first number and a higher middle and last number, 0-10-5. If we are fertilizing very young plants, one to two years old, we use 0-25-0. Any fertilizers we use, we do so sparingly because they do so well here. Most fertilizers are described by the common method of a three numeral identification. Each number indicates the percentage of nitrogen, phosphate and potassium included in the fertilizer.

After we harvest the flowers in the spring, we prune the lilacs. This is when the lilacs start setting their buds for next season, so if we haven’t completed pruning in May or early June we don’t touch them. Lilacs need new growth to set good blooms. Overgrown lilacs need to have a third of the old growth pruned back every season for three years to rejuvenate themselves.

All of our stock was planted in spring as bare root, which means they arrived dormant with stems and a root system but no soil. During shipping they were kept moist with damp cedar shavings. Once we removed them from their packing material, we soaked them for 24 hours before going into the ground. We spaced the plants 5 feet apart and dug the holes about 50 percent wider than the root system and a little deeper because of the compact soil we have here in the dry months. We would backfill some of the soil and fill the hole with water for moisture and settling, and then we would plant it at the same depth as before it was dug with all roots covered. We didn’t amend because we felt it was better to let them adjust to our soil type immediately. Since we have well drained soil, we soaked them after they were planted and watered every three days for the first few years of the growing season.

I hope this helps with any questions you have about growing lilacs, like I said I’m not an expert, but I’ll be happy to try to answer any other questions you have. If I don’t have the answer, I try and find it for you. Just e-mail or give us a call.

Suggested reading:

1) Lilacs: The Genus Syringa Written by: Fr. John L. Fiala.
Publisher: International Lilac Society

2) Quarterly Journal: of the International Lilac Society.