a couple promising zone 10 dry garden plants

Domino’s garden in Los Angeles is slowly taking shape, with everyone pitching in to keep it weeded, mulched, and watered while new plants settle in. (We have availed ourselves of mulch from Griffith Park’s generous compost facility, carload after carload, even despite the numerous tree seedlings it includes. Can’t argue with free.)

A couple plants I gambled on have really impressed me. Salvia ‘Savannah Blue’ seemed full of promise in my Long Beach garden but didn’t really get a fair trial, squeezed in among agaves and succulents which it quickly overran. The soil had been serially enriched over the years with compost, and I suspect life might have been a little too easy for this South African hybrid salvia. In Domino’s garden the soil is simply awful, unamended clay, only approachable for planting after a rain, and mercifully there was lots of that last winter to get the garden started. Already I can see the salvia growing much more densely. Reputedly hardy to zone 8, I did try this salvia in Oregon, but fall planting was not a success. It melted away in the rainy winter. But its overall vigor would suggest a spring planting might be successful, if only as a summer annual or protected in a container, and I’m hoping a couple cuttings root to allow for some more experimentation on the rainy Oregon coast.

In Domino’s garden, luxuriating in full sun but somewhat constrained by unamended soil, I feel that this is a fairer trial than I could give this salvia in my crowded Long Beach garden. Finely cut, leathery, scented pelargonium-like leaves, small violet-blue flowers on slim tapers, it’s really shown what it can do here. Healthy, weed-smothering growth. I anticipate this will need a cutback like, say, Salvia leucantha in late winter/spring. It really is unlike any other salvia I’ve grown, with a remarkably good leaf tailor made for a hot dry garden. Along with its small shrubby habit, it strikes me as very worthy of attention, and I’m excited to track how it performs in Domino’s new garden.

But what’s that silver plant? My thoughts exactly when I found it unlabeled at a local nursery. Lacy like the typical dusty miller but with very thick, succulent-like leaves. The subsequent yellow thistle flowers indicate Centaurea ragusina, the Silver Knapweed, endemic to Croatia. Possibly hardy to zone 7, I grabbed a cutting to try in the Oregon garden — in a well-drained container, of course. It’s been around a while, described by Linnaeus in 1753 and mentioned as worthy by William Robinson in the late 1800s, but it seems to have been superseded in the trade by other centaureas/dusty millers. So far it’s kept a compact profile, not a sprawler. A couple friends have grown it and have only nice things to say about this centaurea, apart from it being hard to find.

Personally, I’m a fan of the lemony yellow thistle flowers, in bud or bloom, but do realize that some may prefer to cut them off to showcase its form and leaves — but then you’d be left with a Victorian bedding plant, right? That’s so 19th century…

I do think if you get the chance, that either of these are worth trialing for a zone 8-10 garden on the dry and sunny side. (The centaurea is hardier than the salvia, down to 0° F.)