As long as freeways have been getting landscaped, oleanders have been contributing their profuse white, pink and red bloom. Heat, exposure and lack of moisture do not seem to bother them. They have become less common recently only because of new diseases that had never before been problematic. The diseases do not necessarily kill all oleanders everywhere, but are serious problems where the nurseries that grow most oleander are located.
The largest oleanders can get more than fifteen feet tall, and can be pruned up as small trees with multiple trunks. Oleander trees with single trunks almost never stand up straight, and do not want to give up their stakes. Because flower clusters develop at the ends of new growth, frequent exterior pruning or shearing inhibits bloom. Dwarf cultivars that are naturally proportionate to their space will bloom better than larger types that need to be pruned for confinement.
Oleander flowers are about an inch or two wide, with five petals, although some have ruffly ‘double’ flowers. Unfortunately, double flowers tend to hang on as they deteriorate after bloom. Some oleanders are slightly fragrant. The name ‘oleander’ is derived from the similarity of their leaves to those of olive trees (‘Olea‘), although oleander leaves can get three times as long.
The Nile River floods annually, inundating everything in its floodplain. Lily of the Nile, Agapanthus africanus, survives by hanging on firmly with a thick network of rubbery roots. It grows and blooms in warm weather as floodwater recedes, and then survives through a long, warm and dry season until the river floods again. It tolerates both drought and flooding, although it prefers more stability.
The blue or white blooms resemble fireworks, and happen to bloom in time for the Fourth of July. The small tubular flowers are neatly arranged in big and round trusses on top of slender and bare stems that stand about two to four feet tall. ‘Storm Cloud’ has darker blue or purplish flowers. Other purple varieties have larger and more pendant flowers (that hang downward from their trusses.)
The dense evergreen foliage is quite luxuriant, and is just as appealing as the bloom is. The rubbery leaves are up to two feet long, and arch outward from basal rosettes. Deteriorating lower leaves are typically obscured by fresh new foliage above. The thick rhizomes can be divided for propagation. Plants known as Agapanthus orientalis may have bigger blooms and wider leaves.
The delightfully clear sky blue flowers of blue plumbago, Plumbago auriculata, seem like they belong with colorful annuals or in a tailored border of colorfully blooming perennials. However, the rampant canes of mature plants are really best in the background where they have room to grow wild. The canes do not climb like vines, but can flop over other shrubbery as high as fifteen feet.
Rounded trusses of small blue flowers begin to bloom sporadically by the end of spring, and continue to bloom in phases until late summer. Supposedly, each subsequent phase should be a bit more profuse than the previous; but not all plants are aware of this. They might bloom best in mid summer, and less profusely later. ‘Alba’ blooms white. Pale foliage indicates a need for fertilizer.
Blue plumbago is not as easy to work with as it seems to be. Once established, it can grow like a weed, and really seems to take care of itself, and it is probably better to allow it to do so. It does not like to be shorn into hedges or geometric shapes as it so often is. Shearing ruins the natural form, eliminates most of the outer canes that provide bloom, and exposes sparse interior growth.
Oregon has good taste. Douglas fir, one of the most useful of timber trees in America, was selected as the state tree. Oregon grape, Mahonia aquifolium, was designated as the state flower. Although the tight clusters of tiny bright yellow flowers that bloom about now may not be as flashy as other state flowers, they contrast handsomely against the glossy and deep dark green foliage.
The pinnately compound evergreen leaves are larger than they seem to be. The smaller individual leaflets that resemble holly get noticed first. They are are not quite as wavy, spiny or thick as leaves of English holly are, so can work well where spiny foliage would be objectionable. Dark grayish blue berries are not abundant, but happen to make good jelly for those who hunt for them.
Mature plants get about five feet tall and broad, and can spread wider like Heavenly bamboo does. Foliage might be a richer shade of deep green, with a slightly more relaxed texture, in partial shade. A few garden varieties are available, including some that are more compact, and some with more rounded leaflets. Old canes should be pruned out as they get replaced by newer canes.
Pictures are probably prettier than the real thing. Australian fuchsia, Correa pulchella, really does bloom with pendulous soft pink flowers through winter when not much else is blooming. However, the flowers are quite small, and the color is rather hazy. The real appeal of Australian fuchsia is that it is so undemanding, and once established, only needs watering a few times through summer.
Mature plants get a bit higher than two feet, and maybe twice as wide, with a low mounding form. The small evergreen leaves have a nice density without any pruning. Obtrusive plants do not mind getting pruned back or even shorn for confinement, but are deprived or their naturally appealing form and texture if pruned too frequently. Good exposure for both sunlight and warmth is important.
Okay, so this is not really the time of year that they should be blooming. Torch lily, Kniphofia uvaria, should bloom in the middle of summer. However, without watering, naturalized plants bloom when the weather prompts them to. Some wait out the warm and dry summer weather to bloom as soon as they get dampened by the first rains. Others bloom in spring, before things get too dry.
Flower stalks can get almost five feet tall, but are more typically about three feet tall. Small tubular flowers are arranged in dense conical trusses on top of these stalks. From the bottom to the top, red flower buds bloom orange, and then fade to yellow, and fold downward against the stalk. Different varieties bloom with more or less of these three colors, and at different times of the year.
The grassy foliage is not much to look at without bloom. By the end of winter, it can look rather grungy. It fluffs back nicely in spring, sort of like overgrown daylily foliage. Overgrown plants, or maybe just a few rhizomes, can be divided anytime. However, they should probably be divided just before the end of winter so that they can enjoy late rain, just before their spring growing season.
From a simple picture, Spanish bayonet, Yucca aloifolia, is indistinguishable from the common giant yucca. The narrow leaves are about two feet long, and flare upward and outward from terminal buds. Plump conical trusses of waxy white flowers with purplish highlights stand vertically just above the foliage. The main difference is that the leaves are more rigid than they appear to be, with nastily sharp terminal spines.
The second most obvious difference becomes apparent as the trunks mature. These trunks get only about four inches wide, which is not quite stout enough to support their own weight. Some might get taller than ten feet, but eventually fall over. Terminal buds of fallen trunks curve upward, and try to grow vertically again. If not pruned away, old foliage browns and lays back against the trunks, like the beards of fan palms.
Some flowers are better left in the garden rather than cut and brought in. Society garlic, Tulbaghia violacea, looks like it would be an ideal cut flower, with nice bare stems. The aroma suggests otherwise. It smells something like a strongly aromatic combination of onion and garlic. Even in the garden, it might be a good idea to keep it at a distance. Deer and rabbits do not mess with it.
Society garlic is sometimes known as pink agapanthus because it has similar foliage and flowers, only much smaller. The tiny flowers are really more lavender pink than pink, and bloom in round clusters on stems about a foot and a half tall in late summer or early autumn. The narrow leaves are only about a quarter of an inch wide, almost grassy, but more rubbery like those of agapanthus.
Mature plants form dense clumps of foliage at least two feet wide. Variegated plants stay much smaller, but are also very likely to revert to green (non-variegated) growth, which if not removed, overwhelms and replaced variegated growth. Society garlic is very easy to divide for propagation. It likes full sun or slight shade. Although somewhat drought tolerant, it prefers regular watering.