Here’s a look at a new groundcover I’m trying out. The plant, Nuttall’s milkvetch (Astragalus nuttallii) is native to coastal Central California, and seems to be adapting easily to my coastal San Diego location–maybe a little too well!
Las Pilitas Nursery, who seems to be the only firm propagating the species, estimates its height to be 3-18 inches and 18 to 36 inches wide. The plant went into the ground October 12, and has topped out at a foot or so high–so far so good. But its spread, now at over six feet, has easily hit more than double the estimated maximum plant size. And that’s with no supplemental watering after the first couple of months in the ground. We’ll see if it slows down as the weather warms and the ground dries out.
The milkvetch bore some of these small, ivory-white flowers on it in October, and it’s never been without them in the intervening six months. Now that the weather is warming, the plant is getting even more interested in flowering.
As much as I enjoy its flowers, my favorite thing about this milkvetch is its delicate foliage. It’s fern-like, and so far has maintained its clean, green-to-grayish green coloration. I have the plant at front edge of the retaining wall next to the front sidewalk, so it’s easy to get face to face with the flowers and leaves. A front of the bed location would also let people enjoy this delicately textured plant.
So, if you’d like a distinctive, delicate, low, mounding groundcover for a dry spot in a zone 9 or 10 landscape, this might be just the ticket, even if the plant might get a little wide and need to be cut back.
PS: I should also mention that one of this milkvetch’s common names is “locoweed,” and the plant is supposedly poisonous. I have no idea whether it’s in the category of nightshade or no more dangerous than tomato plants. Since I have no small children around or pets that get into anything other than catnip, I’ve never let an interesting plant’s supposed toxicity stop me from growing it. But you might consider that before planting a couple acres of it.