This hard-working, graceful perennial deserves to be better known. Ideal for native and rain gardens, Culver’s Root (Veronicastrum) also does well in average garden soil and full sun in most any setting. It lends a strong vertical accent, doesn’t spread or self-seed, has a long bloom period, and the bees adore it. Best of all it needs almost no care. Easy-peasy!
Starting in June, each 2-foot to 5-foot stem will develop racemes, bud up and begin opening from the bottom up. Fluffy arrow-like pink, white or lavender tufts will billow softly in the breeze atop attractive palmate foliage. This plant doesn’t need staking (when grown in full sun) and it stands up well to storms. Deer may sample it occasionally, but they leave it alone for the most part. Remarkably disease resistant, Culver’s root takes heat and humidity in stride.
Origins
There are two main species available; one native to eastern North America and one to Siberia. Most U.S. nativars (improved natives) are based on Veronicastrum virginicum, our native species. They are hardy to zone 3 and up, well-adapted to our local growing conditions.
The common name Culver’s Root or Culver’s Physic is derived from an eighteenth century physician named Culver, who used its bitter roots as a purgative. (Pity the poor patient!)
Based on personal experience, individual plants vary in how quickly they settle in. Some take their good sweet time while others establish immediately. It all depends on the soil and how much sun and moisture they get. Either way, they don’t need pampering.
The cultivar Erica that I planted in rich soil and full sun grows well for me and bloomed the first year. The other cultivars took several years to mature because they are in unamended hard clay, part shade and much drier conditions. But they’ve persevered and bloomed this year.
Culver’s root looks a lot like a tall speedwell (veronica) in flower; in fact it used to be considered a speedwell. Now it has its own classification. The racemes are much larger and airier than speedwell, with mature plants producing tiers of racemes at different heights.
While the straight species is white or pale pink, hybrids come in deeper pink and lavender-blue. The pinks fade but still look lovely.
If you exploit different lighting exposures you can extend the bloom period. In my garden, a cultivar with a southern exposure opens in late May into June. North-facing cultivars open in June and goin into July, with the last one opening as these finish and flowering into August. If I deadhead the first one in early July, it reblooms by late August and into September.
Siting and Companions
As with any tall plant (they can reach 6 feet, but typically get four feet here) place Culver’s Root where its height will be an asset. I have a single specimen of Erica by my mailbox. The light pink flowerheads are fluffy and soft, drawing lots of comments from passersby. This year I have yarrow, gomphrena and a small tangerine agastache with it. Last year agastache Blue Fortune made a particularly good pairing, as the two plants were closer in height.
Medium grasses, coneflowers, globe thistle, landscape roses and phlox would also work. Conifers, arborvitae or a hedge behind will set off the flower spikes beautifully. Salvias and short shrubs look great with it too. Or try Angelica Vicar’s Mead or maybe a tall sedum. This plant is versatile because it doesn’t flop or overtake its neighbors.
Another lovely nativar is Fascination, in lavender-blue. This one has a slimmer habit with beguiling twisty racemes, especially the tallest center spike. I only have two plants right now because I wanted to see how they coped with our winters before buying too many. This cultivar should be massed for best effect, so I’ll be ordering more. One plant looks straggly.
Two other lavender cultivars, Adoration and Apollo, didn’t make it. Had I sited them in richer soil in more sun, perhaps they would have survived. Oh well, you win some, you lose some. That’s gardening.
One drawback is finding hybrids you like for sale. Aside from native nurseries which carry the straight species, your best bet is mail order. Digging Dog Nursery in California is a reliable supplier.
Growing Culver’s Root
As noted earlier, veronicastrum needs a good amount of sun and fairly moist conditions. Some take several years to establish; don’t give up on them! Do give small transplants compost or rich loam and fertilize occasionally. If you put it in clay, loosen and amend the soil. These plants can be slow to break dormancy in spring, so be sure to mark their location. Fortunately they seem to tolerate soggy winters pretty well. Otherwise they need very little to no care.
Different cultivars normally bloom at slightly different times; with our local climate trending warmer, all of mine bloomed earlier than anticipated this year. Not a fault of the plant, just something to keep in mind when pairing it with other flowers.
If desired, you can deadhead the center spike to prolong side blooms. When those are done, remove just the spent top at the nearest leaf axil to encourage a second, smaller bloomset. In fall, cut the foliage to the ground unless you want it to self-seed, in which case you can try withholding mulch and leaving the flowerheads on; it might cast seed very modestly, but I wouldn’t count on it. This plant is very well-behaved and doesn’t self-seed recklessly.
Pollinator Heaven!
If for no other reason, plant this native for the bees. Culver’s root is listed as a top pollinator plant by the Xerces Society. Mine draw honey bees, cabbage whites and wild bumblebees of all kinds, as long as it’s in flower.
I think it’s one of the nicest natives you can plant in regular flowerbeds without worrying it will get “weedy”. So, put this beauty on your wish list right now. I know I’m going to be getting more!
