Lime

Most ripe limes are greenish yellow.

Among citrus, limes are the most diverse. They include more species and hybrids than other types of citrus. Only a few of countless cultivars from centuries of development are available here. Yet, each of these few is very distinct from the others. Most provide juice for culinary application. At least one provides herbal foliage. Few limes are eaten intact.

Dwarfing understock is one commonality of almost all home garden lime trees. Not many grow more than twelve feet tall. With occasional pruning, most might stay less than eight feet tall. All have bright green evergreen foliage and small white flowers. Most have tiny but sharp thorns. Some are more bothersomely thorny. Fruit is green or greenish yellow.

‘Bearss’ lime is the most popular. Its ripe fruits are about three inches long, and resemble greenish lemons. ‘Mexican’ lime provides fruits that are about an inch and a half wide, on thorny stems. ‘Palestine’ lime is thorny also, with round and yellowish fruit that is edible intact. ‘Rangpur’ lime produces bright orange fruit because it is really a sour mandarine.

Horsetail

The allure is more in the form than in the bloom.

            It is no wonder that the many specie of horsetail have been around since the Carboniferous Age. They seem to be impossible to kill! Because they can be so invasive and persistent, they should be confined to planters or areas of the garden where they can be controlled. They should probably be kept away from thickly foliated areas where they can spread and mix with other plants unnoticed.

            Even though they are among the oldest plant specie, they seem well suited to modern architecture. Besides, the narrow areas between modern residences, walkways and driveways are confining by nature. Many modern buildings are even outfitted with awkwardly narrow planter areas that could use plants that get three or four feet tall without spreading out laterally, just as Equisetum hyemale, the most common species of horsetail does. The partial shade and potentially bad drainage in these confined spaces is not a problem.

            The hollow segmented stems are rich green with black or dark brown joints. Some specie of horsetail have symmetrical whorls of wiry stems radiating from their joints. Otherwise, no other foliage is evident. Small knobs on top of the stems produce rusty brown spores. The larger types of horsetail are more likely to become invasive. Equisetum scirpoides stays about half a foot tall and is relatively complaisant. I do not know the identity of the horsetail that I got this picture of; but it has unusually large spore ‘blooms’ and a more relaxed texture.  

California Sycamore

California sycamore develops massively gnarly trunks.

The tallest, largest and oldest trees of the World are all native to California. So are the rarest pine, rarest fir and largest oak. California sycamore, Platanus racemosa, is loyal to this tradition of distinction. Although not the tallest sycamore, it might be the grandest. It develops gnarly and sculpturally irregular form. Some develop multiple massive trunks.

Because of its scale, California sycamore is uncommonly available from nurseries. It is simply not proportionate to home gardens or even big landscapes. Most old specimens are older than the landscapes around them. They are somewhat adaptable to landscape irrigation. However, increased moisture increases potential for spontaneous limb failure.

California sycamore can grow a hundred feet tall with bulky trunks and limbs. Old trees may exhibit scars from shedding limbs throughout their long lifespans. The mottled bark is gray and tan, and roughens only slowly with age. The deciduous foliage of such large trees is very copious through a long defoliation. Foliar tomentum (fuzz) is quite irritating.

Dracaena Palm

Modern dracaena palms are more compact, more colorful and more user friendly than old fashioned sort.

(This article was deferred from yesterday morning.)

            While hoping to find some of the uncommon yuccas that I still lack, I instead encountered some of their friendlier kin in a local nursery. Even though dracaena palm, Cordyline australis, is an old fashioned plant that was probably considered to be too common until the past few decades, many more colorful modern cultivars are restoring its appeal. Classic dracaena palm has olive drab foliage. The nearly as traditional bronze dracaena, ‘Atropurpurea’, has reddish bronze foliage. The more contemporary ‘Red Star’ though is deeper purplish red. ‘Pink Stripe’ has bronzy green leaves with pink edges. ‘Sundance’ has pink in the middle with green edges.

            Modern cultivars also stay shorter so that their abundant foliage can be appreciated on a more personal level. The individual sword shaped leaves are about three feet long and three inches wide, a bit larger than traditional dracaena palm leaves. However, I actually prefer the traditional dracaena palms that can get taller than twenty feet and spread nearly half as wide, with sculptural bare trunks and high branches.  

            Any dracaena palm that gets too tall can be cut back to a more proportionate height. One of my colleagues recommends cutting about a quarter through trunks a year or more prior to cutting back, to stimulate new shoot growth just below the cut. The new growth prevents the trunks from being bare immediately after getting cut back. Overgrown heavily branched trees should first be thinned to decrease their weight before cutting partly through their trunks. Young plants can be cut back to the ground to regenerate with multiple trunks.

            Billowy trusses of tiny pale white flowers add interest at the end of spring, particularly against darker foliage. I am told that the flowers of modern cultivars are slightly fragrant. However, against the olive drab foliage of older dracaena palms, I think that the blooms look rather dusty, and do not smell any better.

Apple

There are countless varieties of apple.

Apples are amazingly diverse. They have been in cultivation for thousands of years. Too many cultivars to document developed during that time. Some ripen as early as summer, while others ripen for late autumn. Some are best for eating fresh, while others are better for cooking, baking or juicing. Some are sugary sweet, while others are impressively tart.

Malus domestica is the general botanical name for most domesticated apples. However, this classification includes countless hybrids of a few species. Some are products of very extensive breeding. Most can grow as large as small shade trees. Grafting onto rootstock limits their size accordingly. Most ‘semi dwarf’ home garden trees are relatively compact.

Apple trees bloom with small but profuse and brilliant white flowers for spring. Flowering crabapple trees generally bloom pink or reddish pink, but produce dinky fruit. Otherwise, apples are about as big as baseballs. Some are significantly bigger or smaller. They can be variable shades of red, yellow or green. Some are striped or blushed with two colors. Their deciduous foliage turns yellow through autumn, and defoliates through winter.

Holly-Leaf Osmanthus

Holly-leaf osmanthus resembles both English holly and Euonymus.

English holly happens to be one of my all time favorite plants, even though it rarely produces the abundant berries that are expected of hollies. Its deep rich green foliage is so glossy and distinctively textured. Because English holly does not mind partial shade, the variegated varieties can add a bit of color where it is too dark for most other plants to bloom. I really do not mind that it is so prickly.

For those who do mind, the holly-leaf osmanthus, Osmanthus heterophyllus (or ilicifolius) is a worthy substitute for English holly that is just as happy with partial shade. The foliage is very similar in appearance, but a bit less glossy, and much less irritating. Holly-leaf osmanthus is sometimes mistaken for English holly, but can be distinguished by its opposite leaves. English holly has alternate leaf arrangement.

Mature holly-leaf osmanthus can get as large as English holly, but rarely does. It is more often less than 10 feet tall and wide, and is somewhat more adaptable to shearing into hedges. ‘Variegatus’, the most popular variety with pale white leaf margins, grows a bit slower and stays more compact, and actually looks better in partial shade than out where it is too exposed. Holly-leaf osmanthus flowers that bloom about now are not much to look at, but produce a delicate fragrance if the weather gets warm.

Leyland Cypress

Leyland cypress ‘was’ an intergeneric hybrid.

Taxonomy is a mess for Leyland cypress, X Cupressocyparis leylandii. The X preceding its genus name indicates that it is an intergeneric hybrid. Monterey cypress, Cupressus macrocarpa is the paternal parent of the original hybrid. Nootka cypress, Chamaecyparis nootkatensis, is the maternal parent. However, its name is now Cupressus nootkatensis.

Therefore, Leyland cypress is now Cupressus X leylandii, and an interspecific hybrid. It inherited attributes from both parents, as well as innate vulnerabilities. It can grow very vigorously to more than thirty feet tall in fifteen years. However, it may not live for another fifteen years afterward. It is very susceptible to cypress canker and a few other diseases.

This is why Leyland cypress often accompanies more permanent but slower vegetation. By the time it finishes its life cycle, the other vegetation is ready to replace it. Most large specimens are less than forty feet tall, with densely conical form. The evergreen foliage is grayish deep green. Less common cultivars are more grayish, yellowish or variegated.

California Wild Rose

Even if bloom is not much to brag about, the rosehips can be pretty and useful.

Prickly thickets of California wild rose, Rosa californica, are not often much to look at, even while adorned with small and sparse pink roses in spring and summer. The fragrant flowers can actually range in color from white to rich pink, and may have more petals, but are not abundant enough to be very impressive at any one time. In autumn though, all the flowers that bloomed in the previous few months leave bright orange or red fruiting structures known as ‘hips’, that linger on the bare canes through winter.

The rose hips of California wild roses had historically been used to make herbal tea because they contain so much vitamin C and have a pleasant flavor. (California wild rose is a ‘tea’ rose but not a hybrid ‘T’ rose.) They can also be made into jelly or sauce. The only problem is that birds like them too, so often take them before anyone else has a chance to.

Heath

Heath for winter. Heather for summer.

Heaths, which are several species of Erica, derive their name from their natural habitats. They are endemic to shrublands of acidic and seasonally dry soil of inferior quality. Such ecosystems, or heaths, do not sustain many big trees or shrubbery. Species from heaths should be resilient to dry chaparral summers. However, they dislike locally alkaline soils.

This is unfortunately why heaths are quite rare within gardens here. They are popular as blooming potted plants for winter, but become scarce afterward. Within planters of potting media, they may grow and bloom for many years. In the ground though, they are likely to languish without acidifying amendment. They prefer the company of coniferous species.

Heath blooms for winter or very early spring. Heather is a similar relation, but blooms for summer or autumn. Floral color ranges from white to pink to rustic purplish pink. Flowers are dinky but abundant. Comparably dinky evergreen leaves are like soft juniper scales. Almost all available heaths grow less than five feet high. Most grow less than a foot high.

White Alder

White alder is not exactly . . . white.

During the summer, the native white alder, Alnus rhombifolia, is a nice shade tree that looks bigger than it really is. By late winter, the bare deciduous canopy has an appealingly picturesque silhouette. This time of year is actually when white alder is typically less appealing, with dead foliage that provides no interesting fall color, but lingers until knocked down by rain or late frost. Yet, even now, it sometimes surprises with these funny looking floral structures that are interesting both in the early winter landscape, and with cut flowers.

In past decades, white alder was an ´expendable’ tree that was put into landscapes for quick gratification while slower but more desirable trees matured. By the time the desirable trees matured, the alders were removed to make more space for the desirables. This technique was practical because, like many fast growing trees, alders do not live very long, so start to deteriorate after about twenty five years anyway. However, alders often live longer than expected.

Mature alders are usually less than fifty feet tall where they are well exposed. They can get at least twice as tall where shaded by other trees or big buildings. Their plump trunks with mostly smooth silvery gray bark make them seem larger than they really are though. Too much water promotes buttressed roots which can displace pavement.