Now is the magic moment for lucky gardeners here in the S.F. Bay Area. Sunny, short days mixed with rain bring some of the best growing conditions of our year. Our gardens experience a brief second spring in the weeks between the first wet storms and the cold weather which usually arrives around winter solstice. But right now, while it’s still warm in the afternoons, the plants are throwing a garden party. The late summer bloomers are still out in force while the winter/spring bloomers are already starting. Summer Salvias (see last months article) are brightening the border with their allies, such as lion’s tail (Leonotis leonurus). Princess flower (Tibouchina urvilleana) is peaking in a cloud of rich purple blossoms, while lavenders continue their unstoppable flowering. And at the same time, the Leucadendrons and Grevilleas which we count on for winter color are perking up and starting to make a statement.
Leucadendrons, from South Africa and Grevilleas, from Australia, are both part of the Proteaceae plant family. These plants share an ability to grow with little irrigation in poor, sandy soil. They require excellent drainage and are frost-tender, but in sandy, coastal, drought-tolerant gardens, they can’t be beat. They bring color, texture, and stature into the winter border, because their growth and bloom is stimulated by the first winter rains just as the summer blooming sages and lavenders, penstemons, and yarrows are putting on their pajamas and preparing for their winter nap.
Over the last several years we have added several Grevilleas to the border at the Garden for the Environment, and we are very excited about how they are developing. Near the north 7th Avenue gate in the exterior border look for Grevillea lanigera ‘coastal gem.’ This Grevillea is spreading over the ground, tumbling down the sandy hillside. Its soft-looking grey foliage earned it the nickname “wooly Grevillea”, and it is covered now with spidery little coral-colored flowers. This plant has been in the ground for two years, and it is beginning to spread. It stays low and tight, but can spread up to six feet wide.
Heading south along 7th Avenue, look for Grevillea rosmarinifolius. This Grevillea does look like a big rosemary plant, and it is beginning to bloom with its distinctive cat’s claw rosy flowers. It is hip high, and sturdy. It would make a wonderful low hedge; no watering, no shearing, no fertilizing, and winter-spring flowers every year!
Next, look for Grevillea juniperina ‘molonglo,’ another ground cover Grevillea. This one is mounding and beginning to spread just below our sink, which you can see through the fence. Most Grevilleas have flowers in the pink/rose/red range, but this one is just starting to show its apricot, almost brownish flowers. This Grevillea would be fun to mix with other gold/yellow flowering plants and grasses. It will arch a little higher than the wooly grevillea, but will also spread wide and tumble down the sandy slope out-competing weeds and stabilizing the soil from erosion.
Continuing south, in front of a bright red single “Altissimo” rose bush, the striking divided ferny foliage of a six-foot shrub may draw your attention. This is Grevillea ‘Ivanhoe.’ Its reddish new foliage and coral, cat’s claw blooms are so striking in flower arrangements that we keep this large shrub/small tree in check just by constant cutting for bouquets.
If you walk up the wooden staircase and turn right, the oval bed to your left includes several large Salvias, blooming dark pink right now. Among them you can spot our newly planted Grevillea ‘Long John.’ This is likely to be our tallest Grevillea as it begins to grow, but its lacy, open foliage will let lots of light through to the other plantings. Its’ large brushy flowers, orange in the bud and opening paler through peaches and pinks are so pretty and dramatic that I imagine this one will get cut frequently for its flowers as well.
The largest of all the Grevilleas, Grevillea robusta, can’t be found at the GFE, but there are several large well-established trees in a public park on Douglass Street at 24th, Noe Courts. Also known as the “silk oak”, these trees are the giants of the Grevillea family. They are too big for San Francisco street trees in most locations, and they also can be rather brittle, and break out branches during winter storms. But they are a useful fast growing tree, they are not fussy about soil and water, and they can add stature to a large garden or park.
The magic of perennial borders is that as one group of plants finishes its yearly cycle and is cut down, it makes room for the next group of plants flush of growth and bloom. Sometimes nature holds her breath and for a moment we get two seasons blooming at once. Now is the magic moment. Visit the Garden for the Environment soon, and enjoy the show!