Photograph by Shari Kaplan
Variegated tobira, often grown as a bush or a hedge, can exhibit green, yellow and white foliage on the same plant, depending on cultivar. It grows best in full sun.
Bulbs and bulb-like plants require specific treatments
By Tony Tomeo
I was just informed at one of my favorite hardware stores that new American flags will not be available for about two more weeks. As new flags become available, certain etiquette should be observed when displaying them in the garden. Flags should not be left out at night unless properly illuminated and should be brought in during rain unless sheltered. The American flag is likely the only feature in a garden that should never come into contact with soil. Although it requires considerable maintenance, it will be seasonable throughout the year.
Before leaving the hardware store, I noticed that more plant bulbs were available now than earlier in the season. This is the time of year that bulbs are planted for early spring bloom. Each species or type of bulb normally becomes available at about the same time it should be planted. Those that should be planted later in winter or early spring for summer bloom will be available later.
The term "bulbs" actually describes five types of subterranean plant parts that accumulate and store resources to ensure survival of the plant through dormancy. True bulbs, such as amaryllis and daffodil, are composed of swollen leaves, known as scales, which are firmly attached to a basal stem plate from which roots emerge.
The other four structures are corms, rhizomes, tubers and tuberous roots. Corms, such as gladiolus (planted in winter), resemble bulbs but are actually composed primarily of a thick basal stem with leaves emerging from the top and roots emerging below. Rhizomes, such as bearded iris, are thick distended stems that grow at or just below the soil surface with roots emerging directly from the underside and foliage emerging from a distal bud. Tubers, like cyclamen, resemble rhizomes, but lack definite structure. Tubers do not "creep," but only expand where they are planted with roots emerging from any part of the stem surface that does not exhibit foliar or floral parts. Tuberous roots, such as dahlias, are actual roots from which blooming stems emerge.
Each of the various types of collective bulbs exhibits a definite top and bottom. Bulbs and corms should be planted with the base of the stem downward. Rhizomes should be oriented so that the rooted side is down and the shoot of the apical bud points approximately upward. Buds should be identified on tubers so that they may be planted with the buds on top. If tuberous roots are planted in clusters, the stem to which they are attached should be on top. Individual tuberous roots are usually planted horizontally.
Many bulbs and bulb-like plants live for many years. Bearded iris rhizomes, for example, branch at each bloom and can multiply profusely in just a few years. However, most require either specific cultural practices to survive beyond their first bloom, or annual replacement. Many garden enthusiasts are disappointed by bulbs that are expected to bloom reliably for many years but actually bloom only once.
Bulbs and bulb-like plants that can be obtained about now for immediate installation include allium, anemone, ranunculus, crocus, freesia, hyacinth, grape hyacinth, narcissus, daffodil, tulip and various iris. Of course, this is not a complete list, and many others may be available through mail-order catalogs or specialty nurseries. Most arrive with specific planting directions and preferred planting depth.
Foliage of the Week: Variegated tobira
The several cultivars of tobira, Pittosporum tobira, each exhibit distinctive characteristics. Height ranges from 2 to 15 feet, while foliar color may be dark green or variegated with yellow or white.
The more common variegated tobira, distinguished by the cultivar name of "Variegata," is usually less than 8 feet tall and wide with grayish green foliage edged with white. It is tolerant to adverse conditions including reflective glare, heat, drought and poor soil if it is well-drained. Full sun exposure is preferred, but light shade is tolerated.
Variegated tobira performs well as a small formal hedge, but should be pruned rather than sheared. Genetically different shoots known as "sports" occasionally appear with dark green foliage. Sports grow faster than the desired variegated parts because they contain more chlorophyll. Some garden enthusiasts find the mix of foliar colors interesting, but risk losing the variegated parts as they are overgrown by the green parts.
Horticulturist Tony Tomeo can be contacted at 408.358.2574 or at LGHORTICULTURE@aol.com.
Los Gatos, California Since 1881
