Silk oaks are known for their coarse, deeply lobed leaves, gray bark and brush-like orange flowers.
Photograph by Shari Kaplan
Certain plants and trees make good 'temporary' landscaping
By Tony Tomeo
When I was about a sophomore in high school, I found a piece of a geranium, approximately three inches long, in a pile of garden debris. I stuck it in the soil in an area of my mother's garden that had not been landscaped. The soil was very hard and "baked." As the geranium grew, I broke stems off and stuck them in a row along the fence until the area was full of geraniums. Although the flowers were a hideously bright pink, they were certainly more appealing than the tall weeds that had previously inhabited the area.
When I finally removed the geraniums to install a rose garden, the soil was in much better condition than it had been prior to the arrival of the geraniums. Their roots and foliar litter and the resulting activity of earthworms had added a minor amount of organic matter to the soil and made it more friable. Because the area had been so densely occupied by the geraniums, there were no weeds to eradicate.
Since then, cuttings from this same geranium have been installed in very large quantities at every home I have lived in, as well as the homes of some of my neighbors. In fact, there is currently a hedge at the end of the driveway growing from a slot about an inch wide where the concrete does not quite meet the fence. It is irrigated on the other side of the fence in my neighbors' garden.
Although I have no intention of replacing the geraniums at the end of the driveway, I have found "temporary landscaping" to be quite useful. It is actually old technology that was once used in large landscapes in which fast-growing, "disposable" trees were installed with the slower but desirable trees. The fast-growing trees would quickly provide shade, but could be removed as the slower trees matured.
Many of these disposable trees grow very easily from cuttings plugged in wherever needed, so they do not cost much, if anything at all. Of course, removal could be a considerable expense, particularly if the trees remain too long. Most trees used as disposables are not practical for more than a few years in the garden because they are too voracious and grow too large. For example, poplars and willows are cute as babies, but they can be quite destructive when they grow up.
Large disposable trees are only very rarely used now because large gardens and landscapes are not as common and because tree protection ordinances may prevent voracious and damaging "temporary" trees from being removed. However, this technique may be used successfully for other landscape features. Perennials and annuals are often installed in very close proximity to each other so that some may be removed as others mature.
I prefer to not actually purchase temporary plant material. If easily grown in the quantity necessary, either from seed or cutting, I am not so hesitant about removing it later. For example, because I can grow unlimited geraniums from cuttings that do not require my attention, it does not seem like such a waste when they need to be removed. (I don't bother to leave geranium cuttings out to dry. After plucking most of the foliage, I just plug them in where I want them to grow and keep them irrigated.)
Of course, there are more species than I can list that are suitable for filling space temporarily and conditioning soil. Replacement with permanent species need not be performed in one procedure, but only as necessary. For example, when installing my mother's rose garden, I only removed geraniums from an area large enough to accommodate the number of roses I was installing at that time.
Tree of the Week: Silk Oak
Because the silk oak, Grevillea robusta, grows rapidly to 40 feet tall or more, it was once popular for temporary use. It is very resilient and performs well in slowly draining soil if irrigation is not too generous, but tolerates typical landscape irrigation if the soil is well drained. Extreme exposure (reflected glare from pavement, walls and roofs) is not a problem.
Silk oak is somewhat messy, dropping considerable foliage in spring and minor amounts in phases through the year. It also drops many seedpods. Limbs are somewhat brittle and can be damaged by wind. Staking and pruning when young will promote structural stability.
Clusters of yellowish-orange flowers emerge in spring. The bark of mature trees is coarse and gray. The deeply "cut" leaves are deep green above and silvery below. The foliage appears finely textured from a distance, but is actually quite coarse.
Horticulturist Tony Tomeo can be contacted at 408.358.2574 or at LGHORTICULTURE@aol.com.
Saratoga, California Since 1955
