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To Mulch Is Not Enough

60727thumbMost plants would prefer the real thing; how they do it in the wild. They drop their leaves, flowers and twigs. Deciduous plants do it mostly in autumn. Evergreens might spread it out through the year. The debris accumulates on the ground below, and decomposes at about the same rate as it accumulates. There is no one there to clean it up. Yet, the natural ecosystems know what to do.

The plants that produce the debris use the nutrients produced by its decomposition. So, with the help of the many microorganisms in the soil, they recycle their own trash. To exploit this resource most efficiently, feeder roots tend to congregate near the surface of the soil where the nutrients are. Because the debris also insulates and shades the soil surface, roots are comfortable there.

Densely forested ecosystems produce the most debris. Many smaller plants in such ecosystems may disperse their roots exclusively into decomposing debris without reaching into soil below. In desert ecosystems, where such debris is minimal, roots are mostly dispersed much deeper to avoid the hot and dry soil surface. They wait for recycled nutrients to leach to them through the soil.

Redwoods, cypresses, many pines and most eucalyptus produce unusually thick layers of debris that decompose slowly. This technique inhibits or prevents the germination of seeds of potentially competitive plants. So, in other words, these trees and other plants had this, as well as moisture retention, soil insulation and nutrient recycling, all figured out long before we knew about mulching.

After we put so much work into raking and disposing of foliar debris that would otherwise accumulate in our gardens, it is ironic that we sometimes need to apply seasoned mulch to compensate for the lack of organic material on the surface of the soil. (Unseasoned mulch draws nitrogen from the soil to sustain its own decomposition.) It does more than merely improve the appearance of otherwise exposed soil. Mulch helps unnatural landscape environments function a bit more naturally.

Posted on by tonytomeo · 15 Comments

Summer Perennials Are Now Blooming

90731thumbAre warm season annuals really the most colorful flowers for summer? Perhaps. They have their limits though. They are also very demanding. They need to be watered very regularly, and should probably be fertilized too. Many need to be deadheaded frequently. After all that, they are only temporary, and will get replaced with cool season annuals in autumn. Perennials are more practical.

Lily-of-the-Nile is likely the most common and most familiar of blooming summer perennials. It is a shame that it blooms only once. Bloom is usually in time for the Fourth of July, and lasts a good long time, but is already fading. Deadheading as the blue or white color is eventually exhausted will not promote subsequent bloom, but will keep the evergreen foliage looking tidy until next year.

Daylily might be the second most popular of summer perennials. Some of the older types bloom only once like lily-of-the-Nile, but various cultivars bloom at various times to prolong the season if a few are grown together in the same garden. The most popular modern cultivars probably bloomed earlier, and will bloom again, perhaps with little time in between. The color range is extensive.

Penstemon are not committed to their natural schedule of blooming in late spring and again in autumn. A good pruning at the end of winter eliminates tired old foliage, and enhances and delays bloom until summer, without compromising the later autumn bloom. Like daylily, a few different varieties of penstemon in the same garden prolong bloom, which can be white, pink, red or purple.

Salvias are a big group of summer perennials that really should be more popular than they are. Some are native. Others are from other chaparral climates. Naturally, they are right at home here. Many bloom about now, and some will bloom again in autumn if deadheaded or pruned back. What they lack in flashy color, they compensate for in resiliency and reliability. They really are tough.

This is by no means a complete list of summer perennials. It does not even include the perennial daisies such as coneflower, black-eyed Susan and gaillardia.

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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.

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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.

Posted on by tonytomeo · 11 Comments

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.

Posted on by tonytomeo · 6 Comments

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.

Posted on by tonytomeo · 20 Comments

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.

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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.

Posted on by tonytomeo · 3 Comments

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.

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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.