Water-wise gardening in the Southwest means accepting the spread of native wildflowers and using them to fill and brighten a landscape or garden. There’s a fine line between weed and wildflower, however.
Some native species spread so easily under the right conditions that they take over a garden. Others might not be native, but were introduced to an area and thrive when Mother Nature cooperates. That’s why we had a “yellow spring.” Last fall, we noticed pretty little spiral seedlings appearing in the dying grass. We wondered what they were, but left them. In the spring, yellow popped up everywhere.
Don’t get me wrong; it was beautiful. But I spent hours trying to identify the plant. I knew it probably was related to mustard, but it didn’t match any of the typical mustard weeds I could find in my searches. And I searched, and searched, for wildflowers and weeds. Here’s a close-up of it in the garden. And guess what it is?
It’s Physaria (one of several types), a member of the mustard family and closely related to yellow alyssum, which I first thought it was. And it has both good and bad qualities. I’ve purchased sweet alyssum before as a bedding plant. And in some searches, it’s listed as a great choice to bring beneficial insects. I can vouch for that, because as I walked across our property on a sunny day, there was a low buzz – bees everywhere. I loved it, but it was a little freaky. And I saw one doe get stung on the face.
Physaria is listed as a native of the Rocky Mountains, and alyssum can be listed as a weed in some Western states. This plant has a taproot about a mile long (slight exaggeration) and really only comes up completely if you moisten the soil and pull. I’ve seen conflicting information on whether it threatens native grasses. We’ll know more as spring progresses.
In the photo above is another weed/wildflower: a native verbena (species Glandularia). I’ve bought plenty of verbenas for rock gardens in lovely colors. And these are beautiful too, especially coming up between the yellow flowers out in open grassy areas. They are more leggy and leafy than the hybrid or garden-variety verbenas, however, and will come up just about anywhere:
Now, I have wildflowers I love that spread like weeds, usually by self-sowing. We usually leave them in place. Some are great for color and flower, some for scent. And the beauty is that they adapt so well to the dry conditions that they fill the garden without us having to purchase, plant, and most of all, water new plants.
An early spring favorite is night-scented stock, also called night stock (Matthiola longipetala). Believe it or not, it’s also a member of the Brassicaceae, or mustard family. The scent in early evening is so pleasant, and we love that these come up near the patio. They’re also reseeding in the grass around the garden!
The blanket flower (Gallardia) has always been a favorite and the previous owners made sure we have plenty in our garden. They thrive in drought and have such vibrant colors, as do Mexican hats, or prairie coneflowers (Ratibida columnifera).
We even admit to leaving a few of the mustard plants intentionally where they complement another plant or look pretty up against a rock or piece of dried wood. We’ll never be able to pull them all or stop the reseeding, and I’m not sure we should. They do attract bees and offer early spring color. But it’s hard enough to get grass to grow in a drought and through various weeds; the physaria species grow most in disturbed areas, so they can fill in to prevent weeds. It is a give and take.
Update in March 2015: The Physaria didn’t choke out the grass last year. It might have delayed grass taking root in a few spots, but we had a beautiful lawn. And yep, it’s already back. I’ve come to accept it, and just want to keep it from spreading across an irrigation ditch to our orchard area. Tim is trying to pull it out of the rock garden beds. I don’t have the energy to fight it. But it’s fun to watch…