California Lilac (Ceanothus spp.)

20180331_182530One of the things missing from so many modern cultivars of plants is the one thing we keep sticking our noses into them for: fragrance.  Yes, looks are good, but why not have both?


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*A handy growing summary chart is at the end of the article.*

California Lilacs (also known as wild lilac, mountain lilac, buck brush, and soap bush) put on a show-stopping display of fragrant clusters of flowers each spring in shades ranging from electric blue to gentle lilac-purple, and some with white or pink.  Depending on conditions, they may even put out a more moderate bloom in late summer to early fall.  Not only will you get that amazing bloom, but your garden will smell like honey in the process.  Not a bad deal!

20180405_154819The various Ceanothus species are native to parts of North America, though there are several endemic specifically to California.  They all share in common a spiny looking growth habit which is where their scientific name comes from.  Keanothos (κεανωθος) is the ancient Greek word for spiny.  They are also all very drought tolerant, requiring little to no irrigation once established.  They are picky about their soil conditions as a result, though.  Drought tolerant plants don’t like overly wet soil, and are also not fond of excessive nutrients, either.  Sadly, we killed one of our Ceanothus over the summer because of an improperly aimed sprinkler that allowed for too much water to soak the soil under the plant.

20190324_170229In the wild, Ceanothus are considered to be a longer living shrub, having about a 15-20 year life span.  In most home gardens their lives tend to be much shorter, likely due to over watering and fertilizer use.  The best approach is to ensure the plants have adequate water when they are in their first year of growth, allowing the soil to dry out in between watering, then to aim any sprinklers so that the ground near by the plant is watered, but not directly hitting the plant itself.  Only in very dry and arid environments will they need additional water other than rainfall.  Since it stops raining here in the Central Valley around April and doesn’t start until October or November, some irrigation is needed, but not much.  You will also need to loosen up heavy clay soils to allow for better drainage.  This is something we have and likely contributed to the shorter life of our plant.

20190309_091904sdThere are many cultivars of Ceanothus available and they come in a wide range of sizes.  You will want to check the dimensions of any you choose, as they can be large and fast growing.  Some grow more upwards, and some are low and spreading, so there is likely one to suit your needs.  They don’t really like hard pruning, so don’t count on that as a method of keeping your shrub in check.  Any pruning you do should be more aimed at lightly shaping it from the outside, but not getting deep into the body to hack off limbs.

20180331_182518Pests are pretty limited, and many are deer resistant due to their spiny limbs and tougher leaves.  They are a huge pollinator magnet and when the plants are in bloom the shrub literally buzzes with all the bees swarming it.  Butterflies are also attracted to the blossoms.  I can’t say I blame them!

20180413_190606Plant Summary:

  • Perennial: Plants will live for several years, but may be shorter lived in wetter, denser soils
  • Evergreen: some varieties may be deciduous, but most are not
  • Height: depends on variety, anywhere from 1-20 feet
  • Width: depends on variety, anywhere from 3-15 feet
  • Sun: full sun, coastal adapted varieties may want some morning or afternoon shade in hot areas
  • Water: little once established, avoid drip irrigation and sprinklers that hit the plant
  • Soil pH: neutral to slightly acidic
  • Soil type: amend heavy clay but not with nutrient rich material
  • Key nutrients: avoid fertilizers
  • Planting time: best to start in fall as temperatures drop to allow roots to get established during the rainy season
  • Zones: 7-10




3 thoughts on “California Lilac (Ceanothus spp.)

  1. Some of the most popular garden varieties lack significant fragrance. The wilder looking sorts are the best anyway. They are best out of the way where they do not need to be pruned. None of them should ever be shorn. Pruning them back is not easy, although pruning away lower stems to promote higher growth is not a problem. For mature specimens, I like to plan ahead for their demise. Some live twenty years. Where irrigates, some might not last ten years. They are very worth it while they last, but when they die, they do so quickly. Don’t blame yourself. It is natural for them.

    Liked by 1 person

    1. The one that died did so very quickly. It was gone within a couple of weeks. Very lovely while it lasted, and very fragrant. We’ll eventually replace it after we do some other space clearing, but we won’t plant one in the same location. It’s just too close to sprinklers there.

      Liked by 1 person

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