Rockrose

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Rockrose is just beginning to bloom.

The first bloom is the best. At least it is purported to be. Many of us who are familiar with any cultivar of rockrose, Cistus, might disagree. Bloom begins in spring and continues through summer. The most profuse bloom can be anytime within that range. Some cultivars bloom sporadically but continually. Others bloom in more distinct phases. Cultivars that start later can bloom into autumn.

Bloom is white, pale pink, rich pink or purplish pink. Individual flowers have five petals and fuzzy centers. Flowers of some of the older cultivars have a prominent rusty red spot at the base of each petal. Smaller flowers are more profuse than larger flowers. The small evergreen leaves of most rockrose are somewhat grayish, with a matte finish. Foliage is aromatic when disturbed or warm.

Most rockrose are appreciated for their low and mounding form. If arranged in a row, they can grow into an artificial berm. Most get at least three times broader than tall. Few get taller than three feet. They all appreciate warm exposure. Once established they do not need much watering. Unfortunately, most rockrose do not live much longer than five years. Few survive more than ten years.

silver dollar gum

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There are actually a few different eucalypti known as silver dollar gum. The most familiar and largest is Eucalyptus polyanthemos. Mature trees that were popularly planted through the 1960s are about forty or fifty feet tall. Some stay smaller. A few that compete with taller trees are more than sixty feet tall. Trunks and limbs are somewhat sculptural, with fibrous bark.

Grayish foliage on limber stems forms a billowy and rounded canopy that blows softly in the breeze. Juvenile leaves are nearly circular, and more silvery gray than adult foliage is, like silver dollars. Ovate adult leaves are about three inches long and half as wide. Tiny flowers with prominent white stamens bloom amongst the adult foliage in spring and summer.

Smaller trees are often pruned aggressively or pollarded so that they continually produce the more desirable juvenile foliage without bloom. The problem with this technique is that it must be repeated every few years or even annually. Otherwise, vigorous secondary growth can get too heavy and break away.

Eucalypti Are Innately Drought Tolerant

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Distinctive foliage provided by red ironbark.

Drought is nothing new here. There could be plenty of rain next winter and for years afterward; but eventually, there will be another series of dry winters, prompting rationing all over again. Landscapers and big box garden centers continue with business as usual. It is up to us to manage our gardens responsibly. Besides native plants, aloes, yuccas, junipers and eucalypti are four groups of formerly popular, drought tolerant plants that are worthy of more attention again.

Eucalypti had gotten a bad reputation even before they became popular the last time around. Tasmanian blue gum, Eucalyptus globulus, that was planted so extensively for wood pulp and timber throughout California, is a huge and extremely messy tree. Yet, it is still the most familiar of the eucalypti.

Garden varieties of eucalypti are much more docile. Even though they drop their evergreen foliage and hard seed capsules throughout the year, they do so on a smaller scale. The tall and elegant lemon gum constantly sheds strips of bark like the Tasmanian blue gum does, but does not get big enough to be too overwhelming.

Because they are so undemanding, and some are somewhat messy, eucalypti are best in unrefined parts of the landscape, and away from lawn. Their mess is no problem over ivy or iceplant. They are happiest where other trees might be unhappy. Generous watering actually inhibits root dispersion, and can cause vigorous but structurally deficient stem growth.

Eucalypti innately prefer to be planted while very young, even from four inch or one gallon (#1) pots. Larger (and more expensive) trees, such as boxed trees, take so long to get established that they get passed up by faster growing tiny (and less expensive) trees. Because they are sensitive to confinement, eucalypti are unfortunately rare in nurseries.

The online catalog of Annie’s Annuals and Perennials, which is famous for excellently weird and undemanding plants, features lemon flowered mallee, red capped gum, silver princess gum, bell fruited mallee and fuchsia gum, all in four inch pots. The bell fruited mallee and fuchsia gum are like large but airy shrubbery that do not get much taller than the eaves.

California Is A Big Place

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There are all kinds of natives.

California is a big place, with more environmental diversity than any other state and most other countries. It includes rainy and cool forests of Del Norte County, and dry and hot deserts of Imperial County. The snowy mountains of Placer County and the mild coastal plains of Los Angeles County are here too. There are hundreds of miles of sandy beaches and big fertile valleys.

Consequently, plants that are native to California are just as diverse. Many that are very well adapted to the environments that they naturally live in are not so well adapted to other environments that may be only a few miles away. They really do not want to go to some of the more divergent climates in other regions.

Coastal redwood that is so happy within its natural range on the foggy western slopes of the coast ranges to the north are not so happy on the drier eastern slopes of the same ranges. It probably would not survive for long in the Mojave Desert. California fan palm from the hot and arid region of Palm Springs languishes on the damp and cool western edge of San Francisco.

Most of the popular California native plants are popular because they do not need much water, if they need any at all. However, some are as unhappy with local climate conditions as exotic plants from other continents are. For example, few plants tolerate drought as well as Joshua tree does. Yet, Joshua tree is likely to grow fast and then rot because winters are too damp for them locally.

Of all the excellent plants that are native to California, the most excellent for local gardens are either the few plants that are native to the local region, or the many others that are native to similar regions. They do not need cold Sierra Nevada Winters, hot Death Valley summers, Mojave Desert aridity or San Francisco fog. They are right at home here.

Even natives need some help adapting to a new garden. Confining their roots to cans while they grow in nurseries is very unnatural for them. Once planted, they will need to be watered while their roots disperse enough to survive on rainfall, or with minimal watering.

Barrel Cactus

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Barrel cactus spines are serious business!

‘Echino’ translates to ‘spiny’; so the genus name of barrel cactus, Echinocactus grusonii, means ‘spiny cactus’. Duh! The nearly spherical and furrowed (ribbed) plants are completely covered with stout and dangerously sharp spines. The most popular variety, known as golden barrel cactus, has pale amber yellow spines. Another variety has white spines. Tan or ruddy spines are rare.

Growth is quite slow. It takes many years for plants to get to three feet tall. Only plants that are quite mature bloom in spring or early summer with bright yellow or orange flowers that develop in a circle, like a halo around the top of the plant. Pink or red flowers are rare. Old plants typically develop a few pups (side-shoots), which may likewise take many years to bloom.

Like most cacti, barrel cactus wants a warm and very sunny location, and very well drained soil. If they do not get watered too much, they can stay potted for many years. However, because they are so nasty, they are not too welcome on porches or patios where most potted plants live. Because they are so heavy and difficult to handle, they are not as portable as they should be.

Cacti Have Bite Without Bark

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Cacti exhibit unique and striking form.

The most inhospitable spots in the garden that no one wants to put any work into seem to be the domain of cacti, whether or not any cacti actually live there. “Oh, I will just put some cactus there!” is cliché in regard to shadeless and dry spots that get too hot with glare from a south-facing wall. Yet, such spots typically continue to be neglected, and the cactus never get planted.

Why are such distinctive and interesting plants considered to be so lowly that they should be banished to the badlands? Why should they be expected to endure what not other plants are expected to endure? After all, there are so many other distinctive xeric plants, like yuccas, agaves and some aloes, that are just as resilient, and according to some, just as lowly.

Cacti really are not as independent as commonly believed. New plants should actually get watered occasionally until they disperse their roots. If they get watered regularly, they need coarse soil that drains very well. Cactus plants that were grown in sheltered spots really can get scaled if planted where they are too harshly exposed during hot weather.

The main problem with cactus is their nasty spines. Simply planting small plants without getting poked is a challenge. Moving big potted specimens or removing overgrown cactus plants without getting seriously perforated can be daunting. So, even though they might do well in the harsh exposure at the curb, they do not belong in such a high traffic area.

Without foliage or conventional stems, cactus are either awkward to prune, or can not be pruned at all. Barrel cactus have only one or very few round stems. If one of these stems gets to wide, it can not be pruned back. Prickly pear cactus is easier to accommodate only because it has enough stems to spare those that grow out of bounds.

What makes cacti so excellent is their distinctive form. Some have strictly upright stems that resemble those of the organ pipe cactus. Some grow as clumps of short and fat stems. Others grow upward and outward with rounded and flat stems like those of the beaver tail cactus.

Weeping Bottlebrush

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Weeping bottlebrush blooms whenever it likes.

It is no wonder that it takes many years to get to fifteen feet tall, and may never get more than twenty feet tall. Weeping bottlebrush, Callistemon viminalis, may grow less than a foot a year, but seems to hang downward two feet. Because the stems are sculptural, and the bark has an appealingly rough texture, most weeping bottlebrush trees are grown with multiple trunks. The brick red bottlebrush flowers that bloom sporadically at any time of the year are more abundant early in summer. Established plants bloom more colorfully with a bit of water, but can probably survive quite a while without it. The evergreen leaves are narrow and mostly less than three inches long. Weeping bottlebrush needs good sun exposure.

Knife-Leaf Wattle

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This wattle sports texture with color.

Even without the bright yellow staminate flowers (fuzzy with prominent stamens) that bloom in late summer or autumn, the grayish foliage of knife-leaf wattle, Acacia cultriformis, is still striking. It contrasts nicely with dark green foliage of pines, redwood and ivy. What seems to be small triangular leaves are actually ‘phyllodes’, which are modified petioles (leaf stalks) of vestigial leaves. They are about half an inch to an inch long, and neatly arranged on stiff stems.

Mature trees do not get much more than ten feet tall, and grow slowly enough to be kept even shorter. They can tolerate a bit of shade from larger trees. However, they bloom more profusely with better exposure. If the pollen is not a problem, the flowers are nice for cutting. So is the foliage, which is complimentary to many other cut flowers. Like almost all acacias, knife-leaf acacia does not require much water once established.

California Pepper Tree

00101It has been naturalized in Southern California long enough to seem to be native. California pepper, Schinus molle, is actually endemic to Peru and adjacent arid regions of South America as far south as Central Argentina. Furthermore, although its small pink fruits with hard black seeds are sometimes used for culinary purposes, it is actually not related to black pepper, and is mildly toxic.

California pepper is as at home here as the name implies. Established and naturalized trees can survive on annual rainfall. They are better foliated if watered a few times through summer, and do not mind average landscape irrigation if their soil does not stay too damp. When they are not dropping a few leaves, they are dropping floral frass or dried berries, so their mess is considerable.

Old trees can eventually get forty feet wide, and almost as tall. Young trees grow rather aggressively. Growth slows with maturity. The distended and irregularly structured trunks and main limbs are picturesquely gnarly, with handsomely flaky tan bark. Foliage and outer stems are delightfully pendulous. The pinnately compound leaves are finely textured, and about three to six inches in length.

Creeping Saint John’s Wort

90717This is not the dreaded aggressively invasive Saint John’s wort that has naturalized in other regions. Nonetheless, creeping Saint John’s wort, Hypericum calycinum, does precisely as the name implies. It creeps, and has naturalized to a less aggressive degree in many spots near the coast. Its vigor is an advantage to many landscapes, but might eventually displease adjacent neighbors.

Creeping Saint John’s wort is a somewhat rustic perennial ground cover that does not need much water once established. It naturalizes in coastal climates because it gets all the water it needs from annual rainfall there. Although evergreen, it looks best if mown as winter ends. It happens to be susceptible to rust, and mowing removes much of the old foliage the the fungus overwinters in.

One to two inch wide bright yellow flowers, with five petals and prominent stamens, start to bloom in June and continue into September. By that time, the paired leaves might be getting tired if not watered, or infested with rust, but should stay presentable until mowing at the end of winter. Crowded plants might get three feet high. Otherwise, growth does not get much more than a foot deep.