Recycle And Repurpose Overgrown Perennials

60720thumbJust like anything else that gets planted in the garden, new perennials seem to be so cute and innocent. They get even better as they mature. Some grow and spread to impressive proportions. Then . . . some perennials get to be too large. Some get overgrown enough to obscure their own appealing characteristics or other plants. Others get crowded enough to inhibit their own bloom.

Lily of the Nile, which is one of the most common and resilient of perennials, grows and blooms indefinitely. It does not spread too quickly, but eventually creeps a few feet every decade or so. However, if it is too healthy, individual shoots can get too crowded to bloom as prolifically as they want to. Also, shoots that get too close to walkways or other plants eventually become obtrusive.

Anyone who has tried to shear encroaching foliage of lily of the Nile knows that doing so ruins the natural lushness of the foliage. Once scalped, it will stay that way until obscured by new foliage that will be just as obtrusive as the removed foliage. The only remedy is to remove the shoots that produce the foliage, leaving the shoots behind them with adequate clearance for their foliage.

Lily of the Nile shoots are not easy to remove. Their rubbery roots have quite a grip! Yet, once removed, the stout stems can be planted as new plants wherever more new plants are desired. They only need to be watered regularly for the first few months until winter, so that they can disperse roots. If dug and replanted in autumn, they generate roots over winter, and are ready to go by spring.

Overly congested colonies of lily of the Nile, as well as African iris and New Zealand flax, can be dug, split into individual shoots, groomed of deteriorating foliage, and then replanted. Because New Zealand flax has such big leaves, it should be processed in autumn or winter; and its leaves should be cut short so that they do not get tattered and floppy while new foliage and shoots grow.

Bird of Paradise can be divided similarly, but carefully because the shoots are surprisingly fragile. However, giant bird of Paradise is a completely different animal. The tallest trunks eventually begin to deteriorate, so get cut down like trees. Basal shoots are left intact to replace them, so only get divided if obtrusive or overly abundant. Most perennials prefer to be divided after bloom.

Canna and calla prefer to be dug and relocated as their foliage dies back after bloom, just before new shoots develop. However, new shoots often develop before older foliage must be cut back.


Arborists Are Modern Tree Surgeons

90724thumbThe terminology has certainly changed over the years. Not many of us remember what tree surgeons were, or that there were actually a few different kinds of tree surgeons, who performed very distinct tasks. Tree surgeons are now known as ‘arborists’. Much of what they used to do is done by other types of horticultural professionals. The work that arborists still perform is ‘arboriculture’.

Back when orchards were still common in the Santa Clara Valley, Orange County, and many of the areas of California that are now urban, those who pruned deciduous fruit trees while dormant in winter were known as tree surgeons. Of course, they did other work that the trees needed through the rest of the year, and harvested fruit as well. They might be known as orchardists nowadays.

Tree surgeons also assembled new orchards, as well as individual trees in home gardens. It used to be standard procedure to install the understock of fruit trees in the first winter, and let it grow through the following year. A tree surgeon would return while it was dormant the following winter, to graft desired scions onto it. This is now done by nurserymen in nurseries that sell finished trees.

The tree surgeons who we now know as arborists are, of course, still important. The tree surgery that we now know as arboriculture is the sort or work that other horticultural professionals are not qualified or able to perform. It involves the biggest of trees that are out of reach from the ground, or even from ladders. There are still a few different kinds of arborists, but most must climb trees.

Arboriculture is the horticulture of trees. Arborists are therefore horticulturists of trees. Those who are certified with the International Society of Arboriculture, or ISA, have passed an examination of their arboricultural expertise, and maintain their credential by continued involvement with the educational seminars, classes and workshops of the ISA. Arborist can assess the health, stability and structural integrity of trees, and prescribe and supervise necessary corrective arboricultural procedures.

Tropical Plants Far From Home

P80811+++++Plants can inhabit nearly every climate on Earth. They live in hot and dry deserts, cold arctic regions, rainforests and just about everywhere in between. Plants seem to have it all figured out. Some even know how to live in our homes as houseplants, although they probably did not plan it that way. Most houseplants are tropical plants that are naturally endemic to tropical ecosystems.

It is actually their tropical heritage that makes them more comfortable in our homes. Tropical climates tend to be conducive to proliferation of all kinds of plants. Those that want to live there must be competitive. Trees compete by growing faster and taller than other trees. Vines compete by climbing the trees. Understory plants that live under taller plants compete by needing less sunlight.

It is these understory plants that do not mind the shade of our homes. Even those that like bright ambient light might never expect to get direct sun exposure. The various ficus trees that might naturally grow tall enough to reach the top of a forest canopy in the wild are still understory plants while young. Because they know how to use resources efficiently, tropical plants do well in pots.

However, these advantages are not so useful out in the garden. Tolerance to partial shade also means that some tropical understory plants need to be sheltered. If too exposed, foliage can get roasted by sunlight or arid wind. (Most tropical climates are more humid than local climates are.) Complaisant roots do not disperse well enough to sustain lush foliage without regular watering.

Ironically, roots of the various ficus trees are very aggressive because they to not disperse deeply, but instead spread out at the surface of the soil where they grow into exposed root buttresses.

The most familiar weakness of tropical plants is their susceptibility to frost. Even though it does not get very cold here, it gets cool enough in winter to offend plants that would never experience cool weather in the wild. Actual frost can severely damage foliage, and can even kill some tropical plants.

Save Some Seed For Later

90717thumbFlowers do not last forever. Whether they last for only a day, or weeks, they all eventually finish what they were designed to do, and then whither and deteriorate. They only need to stay fresh and appealing to pollinators long enough to get pollinated. After all, that is their only job. The next priority is the development of seed and any associated fruit structures that contain the maturing seed.

After bloom, most flowers are just ignored as they deteriorate and fall. Those in big shrubbery, vines and trees are out of reach anyway. Others are either too numerous or too insignificant to worry about. Of course, fruit and fruiting vegetable plants get to produce the fruits that they are grown to produce. Then there are few flowers that need to be ‘deadheaded’ after they are done blooming.

Deadheading is simply the removal of deteriorating flowers. The remains of sterile flowers might be deadheaded because they are unappealing. Deteriorating flowers that would like to produce undesirable seed or fruit after pollination might get deadheaded for the same reason, and to conserve resources that would otherwise be consumed by the developing seed and associated fruit.

However, there are a few flowers that might be left intentionally to provide seed for later. Different flowers finish at different times, and their seed gets sown in particular seasons, but most of those allowed to produce seed should probably be deadheaded through most of their season, with the last few blooms left to go to seed. The same applies to fruiting vegetable plants like pole beans.

Many flowering plants are genetically stable enough to produce progeny that will bloom mostly like the parents. Most are likely to be more variable, or revert to a more genetically stable form, even if it takes a few generations. Sunflower, cosmos, marigold, calendula, morning glory, columbine, snapdragon, campion and hollyhock are all worth trying.

California poppy, alyssum, nasturtium, money plant (honesty) and a few annuals that do not get deadheaded are often happy to sow their own seed.

Cats Do What Cats Want

60706thumbAnyone who has ever owned a cat knows that no one owns a cat. They do whatever they want to do, whenever and however they want to do it. They take orders from no one. If they decide to use a dry spot in the garden as their litterbox, or a tree trunk as their scratching post, it is impossible to dissuade them. They are so smug and arrogant. It is no wonder that so many dogs dislike them.

Cats live in our homes and gardens because we are not as sensible as so many dogs are. We succumb to their charm and devious mind control techniques because they really can be adorable when they want to be. Fortunately, most of us would agree that this sort of symbiosis is mutually beneficial. An occasional delivery of a dead rodent proves that some cats actually work for a living.

As pompous as cats are, they are surprisingly tactful about their poop. Cats that are confined to a home leave it in their litterboxes, and even bury it with kitty litter that absorbs the objectionable aroma. From there, it can be collected and disposed of by human servants. In the garden, cats seem to put considerable effort in burying it out of the way, where it is less likely to offend anyone.

However, what is out of the way to a cat might not be so conveniently situated for others. The most refined and regularly watered gardens might not leave many options for cats, who prefer dusty and dry spots. There is not much to deter cats; so the best option may be to plant and occasionally water something in problematic spots, in conjunction with providing a litterbox somewhere else.

Sneaky cats sometimes use flat or parapet roofs where there is plenty of dry gravel and perhaps other dry detritus. For most single story roofs, it is nearly impossible to obstruct access; but in rare situations, it might be as simple as pruning trees and shrubbery back farther than cats will jump. Obstruction of access to the dusty dry soil of basements and crawlspaces is easier since it usually involves relatively simple repair of vent screens, access hatches or windows.

Weeds Might Produce Hazardous Seeds

90710thumbWeeds are weeds because they grow where they are not wanted. They might be desirable plants in the wild within their native ranges, or beyond their native ranges where they are useful, but for one reason or another, are undesirable in other situations. In fact, many of the most invasive exotic (non-native) weeds were imported because they were useful for something, and then escaped.

Many invasive exotic weeds that were not imported intentionally by humans likely stowed away intentionally by their own means. Some produce edible fruits that contain their seed so that animals who eat the fruit transport and disperse the seed. When animals such as cattle, swine, sheep, horses and chickens are imported, they can bring such seeds with them, and have already done so.

Not all plants have such mutually beneficial relationships with the animal vectors who transport their seed for them. Rather than expend resources on fruit to appeal to, and reward the animals who eat it, they produce seed structures that cling to animals. Most get tangled in the hair of mammals. Some get wedged into cloven hooves. A few are just sticky enough to stick to the feet of birds.

It is sneaky and exploitative, but effective. Most of these sorts of seed structures stick to the fur only for short distances before falling to the ground, where they really want to be. Some types cling for longer distances, in order to take advantages of larger migratory mammals. Dispersion is their objective. Even though they provide no benefit to their vectors, they do not intend to harm them.

However, they sometimes do. Sharply pointed seed structures that are designed to slip smoothly into fur, but not come out easily, can get into eyes, noses, ears and throats of innocent animals. Foxtails are the most dangerous, and sometimes need to be removed by a veterinarian. Burclovers get tangled in soft fur, and sometimes do so in very uncomfortable clusters.

Domestic dogs and cats are more susceptible to the dangers of weed seeds than wild animals are, because their fur is longer, shaggier, and maybe curlier.

Artificial Turf Has Real Advantages

p90512.jpgLawn is the carpeting for our outdoor spaces. Like pavement or decking, it makes the space in or gardens useful for more than growing other plants. Since it is designed to share its space with us, we give it more ground space than any other type of plant. For what it contributes, most of us do not mind giving lawn all the water and attention that it requires. It really seems indispensable.

Realistically though, most of us are lazy; and we really should be using less water in our gardens. Perhaps it would be more polite to say that we should more selectively prioritize the expenditure of limited resources and effort. Lawns that do not get much use are probably not worth all the work and water. There are easier ways of managing extra space than covering it with turf grass lawn.

Whether we like it or not, artificial turf is very undemanding, and requires no water. It is a bit too uniform and perfectly colored to convince those who bother to notice that it is not real turf, but it is still more convincing than old fashioned artificial turf. It is durable enough for children and dogs, as long as no one tries to dig in it. It does well where dark shade prevents real grass from growing.

The cost of artificial turf is an important consideration. It is relatively expensive for those who maintain their own lawns. However, artificial turf that last for many years is less expensive than paying gardeners to mow for just two or three years. The perfect uniformity of color and texture that might be unappealingly unnatural for horticultural purists is so worth the extra expense to perfectionists.

Installation of artificial turf in a new landscape is relatively easy, since irrigation can be installed only for adjacent plants that require it. Replacement of real lawn with artificial turf in an established landscape is much more challenging, or in rare situations, impractical. Trees and adjacent plants that are reliant on lawn irrigation will need to be watered (somewhat) where the original lawn was.

It seems silly and contrary to water conservation to water artificial turf, but it is sometimes necessary until roots of established plants adapt and migrate to other sources of water. This can take a few years for trees that are surrounded only by lawn. Irrigation need not be as frequent as it was to sustain turf grass, but should be sufficient to sustain any other plants while they figure things out.

Boulders In Modern Landscape Design

90703thumbIt is hard to say why boulders and sculptural stone are sometimes incorporated into American landscapes. A long time ago, boulders were only left in landscapes if they were to big and heavy to move out of the way or break apart. Early American landscapes were designed to express dominance over nature by replacing as much of it as possible with unnaturally organized landscapes.

Slowly through history, less refined and more relaxed landscapes became more tolerable, and then became popular as an expression of rebellion to earlier formality. Nowadays, most landscapes are inevitably informal, partly because so many believe that informality is more natural, and partly because few landscape designers will design anything else. Simplicity and symmetry are passe.

This informality allowed for the incorporation of various elements from various styles of landscaping, regardless of how incompatible some of such elements were with each other. Boulders and sculptural stone that had been traditional with many Asian styles of landscape design were added to American landscapes in rather nontraditional fashion. It has been a slow process of evolution.

Boulders are obviously nothing like viable and dynamic plant material, although they do contribute form, texture and color to a landscape. Designers might say that bigger and sculptural boulders add drama without even trying. In some situations, boulders are as functional as they are aesthetically appealing. They can obstruct unwanted traffic or hold back soil that is at a higher elevation.

If they need not conform to any of the various Asian landscape design traditions, there are not many rules for the use of boulders and sculptural stone. Exotic stone that might be incompatible to big open landscapes where exposed endemic stone is visible nearby, might be just fine in enclosed gardens where there is no reference for what is natural.

The standard rule of burying as much as two thirds of a boulder to make it seem as a natural outcropping is only valid if it is intended to look like a natural outcropping.

Rain On The Shade Parade

60622thumbModern urban lifestyles are becoming less conducive to gardening all the time. Bigger and taller homes cast larger shadows over smaller garden spaces. The taller fences between these homes do not help. The densely evergreen trees employed to obscure the views of other larger and taller homes also obscure sunlight. Not much sunlight reaches the ground where shorter plants need it.

While all this is going on, we are supposed to be gardening with more sustainable plants that demand less water. Smaller, shadier and more sheltered gardens should naturally use less water than larger and more exposed gardens need. Yet, the plants that do not mind the shade naturally want more water than plants that want more sunlight. There are not many that are drought tolerant.

Drought tolerant plants are naturally endemic to dry climates. Many are from chaparral regions. Some are from deserts. In such ecosystems where water is too scarce to sustain much foliage, there is not much competition for sunlight. Shade tolerant plants are just the opposite. They are from forested ecosystems with taller and shadier trees. Such ecosystems are sustained by rainfall.

There are quite a few plants that do not mind a bit of shade. Heavenly bamboo, flowering maple, hydrangea, camellia, azalea, rhododendron, holly, daphne and andromeda (Pieris spp.) are some of the more familiar shade tolerant shrubbery; but alas, none are drought tolerant. Nor are the various ferns. Even small shade tolerant trees like dogwood want to be watered regularly.

Most of the plants that tolerate shade but are not too terribly thirsty are groundcover plants or perennials. They are not exactly drought tolerant, but can survive with minimal watering because they do not dry out so much in the shade. Once established in a cool shady environment, plumbago, lily turf, periwinkle Saint John’s wort and coral bells (Heuchera spp.) only need to be watered occasionally through summery weather, although they are thirstier in sunny spots. Both English and Algerian ivy need nothing in the shade.

Summer Turns Up The Heat

90626thumbDoes the heat seem to have come on suddenly this year? There was all that rain through winter, then a quick but delightful spring, and now it is suddenly over a hundred degrees in some places! What happened?! There is certainly nothing abnormal about such warmth in the middle of June. It just comes as a surprise when it arrives so suddenly after such pleasantly mild spring weather.

At least warm weather here is not as dreadful as it is in other climates. It cools down a bit overnight. Humidity is typically (although not always) low. There is typically at least a bit of breeze by late afternoon, just after the worst of the warmth. We need not contend with the sort of dankly humid heat, that lasts all day and into the night without even a slight breeze, that so much of America gets.

Of course, that is no consolation now. By our standards, it is hot. Gardening is no fun, and some of it gets neglected. We become more aware of where shade trees should have been planted. We might also notice wilted or pallid plants that are not getting enough water. Pruning that was delayed while new spring growth matured may need to be delayed a bit longer, until the weather cools.

Unfortunately, the minimal humidity and occasional breezes that make the weather more comfortable for us make it more uncomfortable for the plants in the garden. Plants can realistically tolerate more heat than we can, but prefer it to be in conjunction with humidity. Otherwise, they can lose too much moisture to evapotransipiration (evaporation from foliar surfaces), and wilt or desiccate.

Automated irrigation obviously needs to be adjusted accordingly. Potted plants need more of an increase than those in the ground. Those that are overgrown, in hanging pots, or exposed to the typical evening breezes will be the most consumptive. It is not always easy to know how much they need, but one can be certain that if they are wilting, they need more than they have been getting.

Pots exposed to sunlight can get uncomfortably warm. If cascading or bushy growth does not shade the south sides, smaller potted plants can.