Mound Lily

Mound lily cultivars are generally variegated.

A few of the fifty or so species of Yucca go by the names of Spanish bayonet or Spanish dagger. Both common names apply to Yucca gloriosa. However, only this single species is also the mound lily. Most other Spanish bayonet and Spanish dagger are from deserts or chaparrals. Mound lily is from southeastern North America, so likes periodic watering.

If that is not confusing enough, the curved leaf yucca, which had been Yucca recurvifolia, is now Yucca gloriosa var.(iety) tristis. It has distinctly pliable leaves with a matte surface texture, and is rarely variegated. Mound lily has stiffer and smoother leaves that are more likely to be variegated. It had been rare, but is becoming one of the more popular yuccas. 

Although it does not grow fast, and takes many years to form stout trunks, mound lily can eventually get taller than six feet. Taller floral panicles rise above the densely evergreen foliage. The small and pendulous flowers are pale white, perhaps blushed with brownish purple and pink. The leaves are about a foot or two long and maybe three inches wide, with very sharp terminal spines.

Saint John’s Wort

Saint John’s wort blooms somewhat late.

Although it shares the same common name, Hypericum beanii is not the same sprawling Saint John’s wort that is now so aggressively naturalized within some local ecosystems. It is shrubbier and much more docile. Mature specimens get no more than three feet high and wide. It should be evergreen here, but can get sparse through cooler winter weather.

Bloom begins in the middle of summer and continues at least to early autumn. Cheerfully bright yellow flowers are two inches wide, with five rounded petals around fuzzy centers. The light green and oblong leaves are about two inches long. Stems are rather wiry, and can eventually get shabby. Coppicing as winter ends stimulates fresher vigorous growth.

Saint John’s wort prefers sunny and warm exposure. It is otherwise not very demanding. Regular watering enhances bloom. Yet, established plants can survive without watering. Where coppicing (cutting back to the ground) in late winter is not a problem, Saint John’s wort performs well as a low hedge, or unshorn border. Frequent shearing inhibits bloom. Rust is a potentially bothersome fungal disease.

Drought Tolerance Versus Container Gardening

Drought tolerant plants loathe root confinement.

There are probably just as many reasons to not grow plants in containers as there are reasons to justify container gardening. Some potted plants consume less water than they would in the ground, but only because their demand is proportionate to their limited size. They only want more water in the ground because they can grow larger.

The most drought tolerant of plants are actually the least practical for pots or even large containers. They tolerate drought because they efficiently disperse their roots so extensively. Since they can not adequately disperse their roots in pots, they rely on what they can get from a relatively limited volume of soil. However, even if watered generously, many drought tolerant plants simply can not produce enough finely textured roots to absorb enough moisture.

For example, eucalyptus trees want to begin dispersing their roots while very young. If confined, their long and wiry roots simply go around within their limited volume of soil, trying to find a way out. They can develop a few more fibrous roots than they typically would, but probably not enough to compensate for limited root dispersion.

Wild lilac (Ceanothus spp.), flannel bush, manzanita and smoke tree are not only sensitive to confinement, but have difficulty recovering from confinement if put into the ground after their roots have circled too much within a container. Pines and many other conifers are likewise sensitive to confinement, but some types can recover if the binding roots get severed before they go into the ground.

Plants with dense and fibrous roots are more adaptable to containers. Most succulents and common yucca are good choices. Ferns and some grasses also work nicely, but need to be watered rather regularly. Some types of arborvitae and juniper work better than larger coniferous evergreens. Some small bamboos can stay potted, but not larger types.

Annuals, compact perennials and many ground covers that provide color and fill in space around larger plants are naturally adaptable to container gardening, but their need for regular watering can not be denied. There simply is no practical way of combining container gardening and drought tolerance.

Oleander

Oleanders add color to the commute.

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.

Rockrose

Harsh exposure is fine for rockrose.

The few rudimentary rockroses that were available years ago have been bred into too many cultivars to keep up with. Some of the traditional types can get a few feet tall, with delightfully irregular growth, and flowers that are almost three inches wide. Most of the modern types are relatively dense, low and mounding, like a deep ground cover, with smaller but more profuse flowers. Most bloom pink. Some bloom white. After the initial spring bloom phase, a few flowers continue to bloom sporadically through summer. The grayish and aromatic foliage is not as impressive as the bloom. Rockroses want well drained soil and good warm exposure.

Iris Blooms Almost Any Color

Such cheerful colors are too easy.

Iris got its name from the Greek word for rainbow, because all the colors are included. There are thousands of varieties of bearded iris alone, to display every color except only true red, true black, and perhaps true green. (However, some are convincingly red, black or green.) Then there are as many as three hundred other specie of iris to provide whatever colors that bearded iris lack.

Bearded iris are still the most popular for home gardening because they are so reliably and impressively colorful, and because they are so easy to grow and propagate by division of their spreading rhizomes. Siberian, Japanese and xiphium iris are less common types that spread slower with similar rhizomes. Japanese iris wants quite a bit of water, and is sometimes grown in garden ponds. The others, like most other rhizomatous iris, do not need much water once established. Dutch iris grows from bulbs that do not multiply, and may not even bloom after the first year.

Iris flowers are so distinctive because of their unique symmetry of six paired and fused ‘halves’ that form a triad  of ‘falls’ and ‘standards’. The ‘falls’ are the parts that hang downward. The ‘standards’ that stand upright above are the true flower petals. As if the range of colors were not enough, the falls and standards are very often colored very differently from each other, and adorned with stripes, margins, spots or blotches. Many specie have fragrant flowers. Each flower stalk supports multiple flowers. Some carry quite a few flowers!

Some types of iris are so resilient to neglect that they naturalize and grow wild in abandoned gardens. Bearded iris are more appealing and bloom better with somewhat regular watering, but can survive with only very minimal watering once established. Some iris multiply so freely that they get divided after bloom, and shared with any of the neighbors who will take them. Newly divided rhizomes should be planted laying flat, with the upper surfaces at the surface of the soil.

Western Redbud

Western redbud is a domesticated native.

The thin stems of Western redbud, Cercis occidentalis, that had been bare through winter are now outfitted with an abundance of tiny but almost offensively bright magenta flowers. Rounded or nearly heart shaped leaves will become more prominent as bloom fades. As foliage yellows and falls later in autumn, coffee colored pods that are about two inches long remain until they get dislodged by winter weather. Pods can be very abundant on older or distressed plants, or scarce on young or vigorous plants.

Western redbud is typically grown as a large shrub or a small tree with multiple trunks. Mature trees may stay less than ten feet tall, and do not often get taller than fifteen feet, although they can get more than twice as tall where they need to compete with other trees. Once established, western redbud does not need to be watered, but seems to be happiest if occasionally watered through summer. Seedlings that appear around mature plants should be moved or potted while dormant through winter, and while young, since they will not want to be disturbed once they have dispersed roots.

Natives Are Right At Home

Some native plants should stay wild.

Long before people came here and imported exotic (non-native) plants from all over the world, native plants had been perfectly happy without any pruning, watering or fertilizing. They had always been perfectly happy with local soils, local climates and even occasional wildfires. Many are still happier in the wild than in seemingly more comfortable refined gardens and landscapes.

It really makes sense though. Most exotic plants need to be watered because they are from climates that naturally get more rain. Some want to be fertilized because they are from regions with different soil types. Some plants prefer cooler winters. Others want more humidity. They crave what they would get in their respective native homelands.

However, plants that are native to California are not necessarily native to here. California is a big place with all sorts of climates and soils. For example, the desert fan palm that is native to warm and dry Palm Springs would not be happy in cool and foggy San Francisco. Big leaf maple that likes the cool winters of the Siskiyous does not like the mild winters near the coast of Los Angeles. The best natives are those that are native to a particular region, or similar region.

Also, there are a few native plants that are not so easy to accommodate in every home garden. Both the giant sequoia, which is the biggest tree in the world, and the coastal redwood, which is the tallest trees in the world, are native to California. Even if the local climate is a good fit, the space available may not be.

One of the most difficult problems for so many natives though, is that they are sensitive to the regular watering that most exotic plants require. The regular watering that lawn needs just to survive is enough to rot the roots of plants that do not expect any water between spring and autumn.

Santa Barbara daisy, penstemon and various salvias are some of the favorite native perennials. Wax myrtle and the various ceanothus and manzanitas are interesting shrubbery. Western redbud and toyon can be big shrubs or small trees. California sycamore and various oaks are big trees for big spaces.

Junipers Should Get More Consideration

Old junipers still work like new.

Too much of a good thing eventually gets old. That is how so many of the good junipers that were so popular half a century ago became so unpopular. They became too common, and many were planted into situations that they were not appropriate for. As they matured, many became overgrown or disfigured. Only recently have a few newly introduced modern cultivars restored the appeal of both new and traditional junipers to a generation that is less familiar with their former stigma.

Even though all junipers are evergreen and somewhat similar in regard to foliar texture and their lack of interesting bloom, they demonstrate considerable diversity. Some are low and sprawling ground covers. Others are dense low shrubbery. A few develop as small trees. Branch structure may be densely compact, gracefully arching, rigidly upright, or sculpturally irregular.

Some junipers have yellowish new growth that eventually turns to a more typical deep green. Others are bluish gray throughout. A few rare types are variegated. Almost all junipers have scale-like leaves (like those of cypress). A few have needle-like leaves.

‘Blue Arrow’ and more traditional ‘Skyrocket’ junipers are like short and plump Italian cypress with bluish or gray foliage. ‘Wichita Blue’ juniper is even shorter and plumper, with more sculptural branch structure. However, it is not nearly as irregular and sculptural as the old fashioned ‘Hollywood’ juniper. Modern ‘Gold Star’ and the older ‘Old Gold’ junipers are shrubby types that exhibit arching stems with gold tips.

‘Icee Blue’ is like an improved version of the classic ‘Blue Rug’ juniper, that matures as a shallow bluish ground cover. ‘Blueberry Delight’ juniper is one of the few junipers known for conspicuous fruit, with pretty powdery blue berries against grayish needle-like foliage on trailing stems. ‘Limeglow’ juniper gets a bit deeper, and exhibits chartreuse new growth that turns rich green.

Just because junipers can be shorn certainly does not mean that they should be! Shearing deprives junipers of their naturally appealing texture and form. Instead, junipers should be selectively pruned only where necessary to eliminate growth that is beginning to become obtrusive. Stems should be cut back deeply into the main stems from which they originate, in order to avoid leaving stubs or disfigured stems. Tree junipers like ‘Hollywood’ juniper, as well as overgrown shrubby junipers, can be pruned to expose bare trunks and stems. The gnarly stems and shredding bark can be as appealing as the foliage that obscures them.

Otherwise, once established, junipers do not need much attention or water, and are remarkably resilient. They only rarely get infested with spider mites or scale insects, or get damaged by disease. They only want good sun exposure.

Manzanita

Shrubby manzanitas develop sculptural stems with shiny cinnamon brown bark.

There are more than a hundred specie of Manzanita, Arctostaphylos spp., that range in size and form from creeping ground covers to small trees that can get almost twenty feet tall. (They are more commonly known by their cultivar names than by their specie names.) Arctostaphylos ‘Emerald Carpet’ is as the name implies a nice low groundcover for dry slopes. Arctostaphylos ‘Doctor Hurd’ is a shrubby small tree that is often pruned to expose strikingly sculptural trunks that are as smooth and rich brown as a chestnut.

Abundant trusses of tiny ‘urn’ shaped flowers bloom about now. Almost all are pale white. A few are pale pink. The subsequent red berries typically get eaten by birds before anyone else sees them. The evergreen foliage is quite dense. Individual leaves are rather small and disproportionately thick.

Manzanita should be planted while small, because larger plants are more susceptible to rot. New plants want to be watered to prevent desiccation until they disperse their roots. If planted in autumn, they get enough water from rain through winter (typically), so that they only want occasional watering through the following spring and summer. Once established, they do not want much water at all, and can be damaged by fertilizer. The happiest plants are satisfied with what they get from rain after they get established.