How to Prune CA Buckwheat

My most popular blog posts were on pruning sages, here and here. Clearly people are interested in, and possibly confused about, how to prune native shrubs.

Many of the wild sages that are used in native gardens (Salvia clevelandii, S. leucophylla and cultivars of both, to name a few) are fast growing, woody shrubs. Experts suggest that gardeners should prune and shape these plants when they are young, before they grow these woody stems. The wood does not always grow new leaves, so pruning into it can expose dead branches on a misshapen plant. On the other hand, I have seen some amazing sages with fascinating, twisty structures. Over the years, however, these plants seem to age like some humans, becoming gnarly and bald with time.

I suppose that if I were diligent about tip pruning new growth, maybe I could minimize the dead thatch that seems to accumulate beneath a leafy top of many of my mature sages. However, I rarely succeed at this, and so I merely replace these older, woody plants. A similar problem happens with California buckwheat, Eriogonum fasciculatum.

California Buckwheat

This common California native occurs throughout much of the state. It is a tough evergreen shrub that blooms in the heat of the summer when many other plants have started to shut down. Its lovely cream to white flower clusters feed many pollinators, while adding floral color to the summer native garden.

The following gallery shows buckwheat in the South Pasadena Nature Park. It usually blooms from June to September and beyond. Last summer’s record heat in July caused some of the buckwheat flowers to dry up, but we continue to have a few blooms throughout much of the year. Mature flowers turn a luscious rust color in fall and winter.

Pruning buckwheat

Though California buckwheat is similar to wild sages, I find it to be somewhat less woody, and so I thought that maybe it could take harder pruning than is recommended for the sages. However, most of the pruning advice that I have seen cautions against hard pruning.

Care & Maintenance of California Native Plant Gardens (2006, O’Brien, Landis, and Mackey, p. 115) provides some of the clearest information on maintaining native plants. Unfortunately this book is no longer in print and very hard to find. Nonetheless, according to O’Brien, Landis and Mackey (p.115)

“All that is necessary [for wild buckwhat] is to dead-head the plants … For Eriogonum fasciculatum, “don’t prune back into old, dormant wood. Plants will not always recover. Give plants plenty of space. Groundcover types are vigorous and wide spreading, and will not look good if pruned to a hard edge. Pinch or lightly prune the center after planting, or else the center of the plant will either mound up or thin out. Lightly head back in late fall if you want denser growth.”

In the book, California Native Plants for the Garden, Bornstein, Fross and O’Brien write (p. 102)

“With some effort, you can even clip California buckwheat into a low hedge, but this much pruning would sacrifice most of the flowers.”

Yerba Buena Nursery recommends:

“Deadhead and prune dead growth in fall; coppicing can renew woody specimen but may kill plant.”

On the amazing Las Pilitas website created by the late Bert Wilson, the “Plant Specific Pruning Tips” advises:

“Eriogonum, Buckwheat, late summer, remove dead material if needed”

Mike Evans of Tree of Life Nursery has created and uploaded to their website an excellent, concise guide, Creating and Caring for Your Native Garden. In the maintenance sections, p. 8, he suggests:

“Woody subshrubs such as sage, buckwheat, and coastal sunflower will benefit from an annual pruning at the beginning of the fall season.”

Gardeners’ advice

Another great source of gardening information is from knowledgable hobbyists. Native plant gardeners actively share information on several internet forums. Gardening with Natives is one such group. This forum was created by the Santa Clara Chapter of the California Native Plant Society. I have read several posts in which gardeners describe pruning their California buckwheats annually, sometimes cutting it back fairly hard:

Buckwheat I find can be pruned hard, to replicate a fire cycle, and easily pop out of an ugly haircut by the next season. (R.S.)

These are all very helpful reads: 

1. http://www.yerbabuenanursery.com/Pruning_Calendar.php

2. http://www.heaviland.net/maintaining-california-native-plants/

3. http://www.laspilitas.com/garden/howto/pruning.htm

4. California Native Gardening: A Month-by-Month Guide, by Helen Popper

Most buckwheat get deadheaded after blooming.  Since the seeds are valuable food source for wildlife, AND the rust color flowers provide a nice fall decoration, it’s best to wait with pruning until the end of fall.  I usually wait until January, and trim before only to clear a path.  CA buckwheat (E. fasciculatum) is different from others in that it can be cut into the foliage and its size reduced to about 50% or even more.  Before pruning, I like to roll the dry flowers between my gloved hands to break them up, and then sprinkle them around the garden as mulch :).  This species spreads by layering, so rooted sections can be divided and transplanted, or be potted up to share this time of year. (A.G.)

These before and after photos show how I prune CA buckwheat.  About 1/3rd of the plant is removed.  Some of the cut off stems can be stuck into the moist ground or in moist potting mix to propagate more plants.

While my client wanted me to do this maintenance in her garden this month, as she is preparing for a long trip, I usually wait until January to do this pruning in my own and other gardens (along with that of CA fuchsia, goldenrod, white sage, etc.)—so the plants provide habitat for as long as possible.  For example, we see many songbirds hanging, sometimes upside down, on the stems of our CA fuchsia to enjoy their seeds during late fall and winter.  Not to mention the plants’ lovely, fall season decoration in the garden this time of year.  (A.G.)

My buckwheat

I’d like to describe two examples – one in my own garden, the other in the nature park – of how this plant grows and how we pruned it. The first is the buckwheat I planted in my six-foot wide parkway garden in 2002. Over the years it has grown with no supplemental water. It is a bit wild, and I have had to prune it back from the street and sidewalk. The plant developed a tangle of dead stems (about 18 inches high) beneath the actively growing stems, leaves and flowers.

Although this buckwheat blooms each year and the amount of pruning that I have had to do to keep the sidewalk and street clear has been minimal, I really am not fond of the dry, thatchy twigs beneath the thin cover of green leaves. With other plants, as mentioned above, I have tried correct this condition – usually way too late – with judicious pruning. Unfortunately, I seem to fail in “judicious pruning.” Although I begin with the best intensions, I usually end up pruning the sh*t out of the plant.

So once again, I approached the unassuming buckwheat with clippers in hand. Had it been in possession of legs, this would have been a good time to run. I cut it nearly to the ground (see gallery below). I suspect that my buckwheat may have a hard time coming back from my heavy-handed treatment. Nonetheless, after 16 years I am ready to say good-bye, if necessary. If it does die or decline, I will plant other buckwheats because they bloom in summer and attract so many bees and insects. I promise (New Years resolution) to tip prune it when young, and once it has become established I will prune it more gently each year.

A gallery of photos follows with the life history of my parkway CA buckwheat.

At the nature park

The second buckwheat I’d like to discuss is growing on a busy street at the entrance to our local nature park. Few plants have succeeded in this hot, sunny, unirrigated location, and so I am very reluctant to remove this plant. The city maintenance crew, however, decided that it would look better as a cuboid (an elongated cube). I was pretty upset about this harsh treatment. However, it seems to be coming back okay. I plan to prune the growing tips to try to encourage it to fill in more. I will continue to follow both plants and post pictures in the years to come.

What has worked for your California buckwheat?