Cover Ground With Ground Cover

Trailing rosemary eventually gets somewhat deep.

Within the outdoor rooms of home gardens, shade trees are ceilings, shrubs and hedges are walls, and turf and ground cover plants are floors. That is why the selection of plants for such purposes is as important as the selection of paint and carpet for indoors. Among ground cover plants, durable turf grasses for lawns are the most common and functional.

There are so many more types of ground cover plants besides turf grasses though. A few of the lower, denser and more resilient types of ground cover plants can function as turf if necessary. Many more function as mulch to control erosion, contain dust or conceal mud. Many inhibit proliferation of weeds. Some retain a bit more moisture than they consume.

Appropriate ground cover plants most definitely have many advantages. They also have certain disadvantages. Although most require less maintenance than the weeds that they exclude, they require more maintenance than simple mulch. Also, most require irrigation. They might be trailing perennials, sprawling shrubbery, or unsupported wandering vines.

Trailing gazania, Hottentot fig (freeway ‘ice plant’) and various ice plants are some of the more popular perennial ground cover plants. They and others migrate by trailing stolons or rhizomes. They are among the lower and more compact types of ground cover plants. Some need no more pruning than edging. Many propagate easily by division or cuttings.

Sprawling sorts of juniper, ceanothus, cotoneaster, myoporum and rosemary are shrubby ground cover plants. They get significantly deeper than perennial plants, and some sorts can eventually get too overgrown to be practical. Rosemary, myoporum and cotoneaster are conducive to shearing as they mature. Ceanothus and juniper need significant area.

English ivy, Algerian ivy and star jasmine are vining ground cover plants that should stay rather low if properly maintained. However, they can climb into shrubbery and trees, and even buildings. The ivies are famously aggressive, and spread indefinitely by rooting as they migrate. Severe pruning can renovate some overgrown vining ground cover plants. Bougainville gets rather shrubby and deep, even without support.

Not All Plants Like Fads.

Ornate pots and planters can be as decorative as the plants within them, and provide extra accommodation for more plants.

Like so many fads too often are, container gardening is overrated, and is actually contrary to the currently most faddish of fads; sustainability. Plants in containers need more regular watering than those that can disperse their roots more extensively into the ground. Those that are so indulged also want fertilizer to be applied more regularly, but are more likely to be damaged if fertilized too generously. Because confinement is stressful, plants in containers are innately more susceptible to disease and pests. Some plants need more pruning for confinement.

Then there are the problems with the containers. If exposed to sunlight, thin plastic containers get warm enough to cook roots within. Pots that do not drain adequately or that sit in their own drainage basins can stay saturated enough to kill roots. Water in drainage basins allows mosquitoes to proliferate. Seepage from large pots can rot decks and stain pavement. Self watering containers work nicely for houseplants (if used properly!), but lack drainage, so can not be used out where they are exposed to rain.

The advantages to container gardening are actually quite limited. Containers are obviously needed for houseplants, and where exposed soil is not available, like on balconies. They are also convenient for plants that want better soil than they can get in the garden, especially if the rest of the garden is responsibly landscaped with sustainably undemanding plants that do not require soil amendment or regular watering. Frost sensitive plants can be moved easily to sheltered locations if contained. Flashy plants like orchids and tuberous begonias that get displayed prominently while blooming can be concealed while not so impressive.

Of course there are many pendulous plants like Boston fern, spider plant, string or pearls and burro’s tail that really are at their best in hanging pots. It is also hard to deny that there are all sorts of artsy containers, like colorfully glazed pots and sculptural concrete urns, which are appealing enough to justify growing plants in them, even if just to show off the fun containers. Bonsai requires containers, but that is another big topic!

Utilitarian Garden Features Became Aesthetic

Nasturtium used to be more utilitarian.

Gardening is fun. Furthermore, gardens are pretty. Some gardens also produce fruits and vegetables. Not very long ago, production of fruits and vegetables was more of a priority for more gardens. Some big gardens generated firewood and a bit of forage for livestock. Contemporary abundances allowed gardening to become more aesthetic than utilitarian.

Such abundance may not seem so apparent while so many of society could benefit from a bit more. People work more than ever to earn resources to purchase produce that they can not grow in their gardens while working so much. It has become more feasible to do so. Landscape maintenance is just another expense that many would prefer to eliminate.

Nonetheless, some popular features within modern home gardens evolved from formerly utilitarian features. Many such utilitarian features were common within the infrastructures of home gardens prior to the development of any modern technology that replaced them. Some were popular only because such technology was either expensive or uncommon.

Shade trees are among the most traditional and perhaps more recognizably utilitarian of landscape features. Although, even they have evolved. With modern air conditioning and insulation, their shade is less important than their aesthetic appeal. Window screens and rain gutters are also modern technologies that made particular garden features obsolete.

Window boxes, which are now mere ornamental features, were originally popularized for aromatic vegetation, to repel insects from windows. Rosemary, nasturtium, ivy geranium and petunia had always been some of the more popular repellent plants for this purpose. They do not obscure much sunlight as they cascade delightfully outward and downward.

Foundation plantings, which now merely soften the perpendicularity of vertical walls and horizontal garden spaces, were also utilitarian features. Compact and resilient shrubbery or perennials inhibited erosion caused by rain falling from eaves above. They obstructed splattering mud from below also. Indian hawthorn and lily of the Nile were quite effective. They could survive through summer without much irrigation, but then survive excessive moisture through winter.

Catch Weeds Before They Go To Seed.

Seed pods not only look unkempt and inhibit continued bloom, but can disperse too many seeds of otherwise worthy plants.

It may seem futile to pull certain weeds this late in the season. Those in unrefined parts of the garden that get little or no irrigation might be so dry that they only deteriorate and scatter their abundant seeds when pulled. The soil may be so dry that roots are difficult to extract, especially since the drying foliage now separates from the roots so easily. The only hope is that removal of dying weeds might eliminate at least some of the seeds for the next generation of weeds.

Foxtail and burrclover are not only annoying, but are also dangerous to dogs and cats as their seeds mature and dry. After all, the seeds rely on animals for dispersion, so intentionally stick to fur. The problem is that seeds can get stuck in more than fur, and sometimes get into ears, eyes, nostrils and elsewhere. Seeds from a few other weeds can do the same.

Cheeseweed is not a dangerous weed, and is relatively easy to eradicate. The roots even stay attached to the stems when they get pulled. The problem with leaving them to mature is that they become infested with rust (a fungal disease) that spreads to other desirable plants. Saint John’s wort, snapdragons and roses are particularly susceptible to rust.

Feral Jupiter’s beard and montbretia that grow where they were not intentionally planted are often allowed to bloom before getting pulled. However, after bloom, stems separate so easily from roots that most of the roots remain to regenerate as soon as they are able. If left long enough after bloom, both Jupiter’s beard and montbretia sow seeds to infest even more.

Fortnight lily (or African iris) are not often a weed, but can get that way if their seed capsules are not removed before they mature and pop open. Besides, development of these capsules diverts resources from continued bloom. It is best to remove the capsules before they get floppy, and to remove as much of the finished flower stem as possible without removing stems that have not yet bloomed.

Both dusty miller and coleus are grown for their distinctive foliage but not their bloom. Flowering stems stretch and exhibit inferior foliar color and texture, so can actually get snipped before they bloom.

Mulch Retains Moisture And Insulates

Mulch helps to insulate the soil.

Nature is smart. It should be. It has been operating efficiently since the beginning of time. That is certainly longer than anyone has been gardening in defiance of nature. Imported plants that need unnatural watering and soil amendment continue to benefit from nature. Some assets, such as weather, are direct from nature. Some, such as mulch, are copied.

Summers are long, dry and somewhat warm here. Without rain, there is plenty of time for the soil that roots inhabit to become dry. Warmth and aridity increase the consumption of moisture by plant species that are not accustomed to such extensively dry weather. That is precisely why landscapes and home gardens are so reliant on supplemental irrigation.

Because water is expensive, plants that do not require much of it are popular. Automated irrigation systems should operate as efficiently as possible to minimize waste. Since turf grass is very consumptive, lawns should not be overly expansive. Conservation of water is common here. There are several techniques for doing so. Mulch is one of the simplest.

Although adding mulch to a garden is unnatural, it works like the natural detritus within a forest. It retains moisture and insulates the surface of the soil. Without mulch, surface soil can become uncomfortably dry and warm for roots. Mulch also inhibits the proliferation of weeds. Because weeds consume moisture, their absence indirectly conserves moisture.

Mulch generally goes into the garden during early spring, before weed seed germinates, and after the removal of the detritus of winter. It can be practical at any time though, even as the soil becomes dry and dusty through summer. Various forms of mulch are available from garden centers. Home compost works splendidly, but costs nothing more than labor.

Alternatively, several types of groundcover can function as mulch. Some types consume more moisture than they conserve, but exclude weeds. Some types, such as ceanothus, lantana and licorice plant, might not crave any more water than the plants they surround. Their maintenance should involve less effort than removal of weeds which they displace. They are more visually appealing anyway.

Squirrels Fear The Unknown Too

Pierre Francois dutifully protects ripening fruit.

It is embarrassing when my mother teaches me a practical gardening technique that I should have known about, especially if the particular technique is as simple and downright silly as what my mother does to protect ripening fruit from squirrels. A friend of hers suggested it; and it seems to be significantly more effective than the few fancier ideas that I recommended.

I should first mention that there is nothing new about repelling animal pests with effigies of other animals that they are afraid of. Scarecrows and stuffed snakes and owls have been around for centuries. As the name implies, scarecrows scare crows who perceive them to be potentially troublesome people. Rats and terrestrial rodents avoid snakes. Squirrels and some birds are afraid of owls.

When I was in about the fourth grade, I remember that National Geographic World magazine (which is now National Geographic Kids) featured a silhouette of a predatory bird that could be cut out and taped to windows to deter birds that might otherwise break their necks as they tried to fly through the clear glass. The associated article explained that the cut-out silhouette was effective because birds instinctively knew what to fear. A silhouette of a harmless seagull would not have been as effective.

However, some deterrents are not so specific, but instead rely on the fear of the unknown. Beach balls outfitted with decals of huge eyes look weird in the garden, but work because so many birds have bird brains that think such contraptions are big, scary and possibly predatory animals. Flash tape and old compact discs work simply because birds do not know what the reflected flashes are.

Scarecrows and other inanimate effigies should be relocated occasionally so they seem to be alive. They should stay near what they are in the garden to protect, and not loiter when it is gone. For example, if protecting ripening fruit, they should leave after the last of the fruit is gone. Otherwise, the target pest animals realize that they are fake or dead. Beach balls, flash tape and compact discs are more animated, so need not be moved so much, if at all, but are too tacky to stay all year.

All this may seem complicated, but can be simple enough for my mother to master with . . . well, allow me to explain.

Pierre Francois is a cute, fuzzy and seemingly French plush toy bunny made in China, who knows all about protecting ripening fruit from squirrels. (‘Stuffed animal’ is no longer politically correct.) After seeing how expensive a fake owl would be, my mother put Mr. Francois in the peach tree. He and his sort are free if borrowed (stolen) from the grandchildren, or very cheap at garage sales or thrift stores. Although cute and soft to us, Mr. Francois is big, intimidating and unfamiliar to squirrels. Before the squirrels get acquainted with him, the peaches will have been harvested, and Pierre Francois will have been reassigned to an apple tree.

Saturation Of Soil Distresses Roots

Some riparian plants tolerate soil saturation.

Saturation of the soil should be a rare problem within the local chaparral climates. Water is a limited resource. That is why plants that are not native or endemic to other chaparral or desert climates rely on supplemental irrigation. Many exotic species would not survive through the locally long and dry summers without it. Water is only sufficient during winter.

The unfortunate reality is that soil saturation is among the more common problems within landscapes that rely on gardeners. Although most gardeners are proficient with irrigation, some are not. They would prefer to irrigate too generously than risk desiccation. They do not assume the expense of the water, or of the plant material that succumbs to saturation.

Although significantly less common within home gardens that do not rely on professional gardeners, soil saturation is possible. It occasionally happens within pots or planters that lack adequate drainage, or if the drainage becomes clogged. Saucers that contain water that would otherwise damage decking or flooring might inhibit drainage if constantly full.

Besides within pots and planters, saturation is more likely within dense garden soil than within coarser soil. Downspouts could saturate surrounding soil through the rainy winter season. Leaky plumbing might do the same at any time, even if it is merely irrigation pipe that leaks only while operating. Of course, excessive irrigation produces most saturation.

Saturaturation deprives soil or medium of aeration. Roots avoid soil or medium that lacks adequate aeration. Trees and large shrubbery therefore disperse most of their roots near the surface of saturated soil. Such shallow root dispersion limits stability. The expansion of such shallow roots displaces and fractures pavement and curbs, and heaves lawn turf.

Excessive irrigation causes soil saturation during summer. Excessive frequency is more likely to cause saturation than excessive volumes of water. Unfortunately, it is impossible to prescribe appropriate irrigation schedules and application rates. Climate, soil type and plant material are all relevant considerations. Moisture requirements change seasonally, and from year to year, as plants mature.

Taking It To The Streets

Tipu tree is the topic for tomorrow.

No matter how unique the individual gardens are, conforming street trees really unify a neighborhood. Streets of tract homes are typically planted with a common street tree that is complimentary to the architectural styles of the homes, and is complaisant to the difficulties of life at the curb. Neighborhoods of mixed architectural styles sometimes have difficulty finding a tree that suits every home, so often select two or more options. Older neighborhoods are not quite as selective about conforming street trees because so many various trees get mixed in over the years.

Before selecting a street tree, it is best to inquire with the particular municipality about designated street trees. Home owners associations generally install their own trees where needed, with little or no regard for the preferences of individual residents. Some urban neighborhoods (that are not home owner associations) are nearly as selective, requiring individual home owners to maintain a specific street tree or trees. Others do not require street trees, but limit selection for those who desire them. Selection is very often limited to only a single species.

There are of course many rural and unincorporated neighborhoods without limitations for street trees, and neighborhoods where limitations simply are not enforced. However, selection should still be limited to trees that are appropriate for curbside planting. Such trees should have high branch structure so that they can be pruned for clearance above the largest of trucks that can use the roadway. They should be reasonably clean, and not produce anything that could be messy on cars parked below. Roots should be complaisant with concrete curbs and sidewalks, particularly where space is limited. Foliage and bark must be resilient to harsh exposure and enhanced glare (from surrounding pavement).

London plane (sycamore) and crape myrtle trees are the two most common street trees planted by landscapers, and are the most commonly pre-designated street trees, but are actually not the best of choices. London plane is popular among landscapers because it can survive the neglect that landscapers are notorious for, but has aggressive roots that eventually damage concrete, especially since landscapers waste so much water and keep the soil saturated. Crape myrtle is remarkably colorful both in bloom and with fall color, and has remarkably complaisant roots, but does not get tall enough for adequate clearance, and often gets infested with insects that drop sticky honeydew on parked cars.

This was the topic for yesterday.

Aquatic Plants Are All Wet

Both cattail and duckweed are native.

Home gardens and landscapes should be compatible with their respective climates. For local chaparral climates, plants that do not need much watering through the long and dry summers are appropriate. Aquatic plants are the extreme opposite. They require regular replenishment of the ponds that they inhabit. Arid warmth increases their need for water.

Aquatic plant can not be ‘drought tolerant’. Several, such as duckweed, water lettuce and water hyacinth, float over the surface of water. Water lily and lotus inhabit the mud below the water, and extend their foliage to float over the surface of the water. Waterweeds stay completely submerged, with or without roots. Aquatic plants need water for their survival.

Marginally aquatic plants are somewhat less dependent on water. Cattail and yellow flag iris inhabit shallow ponds and saturated soil, but can survive if their situations drain for a while. If they stay too dry for too long, they can initiate dormancy, and then recover when saturation resumes. Canna inhabits either shores of shallow ponds, or evenly moist soil.

Regardless, all aquatic plants require maintenance that is completely different from what terrestrial plants require. Even those that need only minimal maintenance will eventually necessitate muddy and messy interaction. Much of such interaction is under water that is difficult to see through while murky. Aquatic plants are innately heavy and totally sloppy.

Moreover, some common aquatic plants grow like weeds. Water hyacinth and giant reed are two of the most invasive exotic species in California. So, not only are they sloppy, but they are also voluminous! Because they are very invasive, they should not inhabit ponds that they could escape. Besides, giant reed is too overwhelming for most home gardens.

Few home gardens include natural ponds or water sources to contain as ponds. Garden ponds are therefore mostly contained within some sort of sealed infrastructure, and need replenishment to compensate for evaporation. Fountains aerate the water for a healthier ecosystem, but also increase evaporation. Some tall aquatic plants also consume water, as the foliage that extends above water transpires.

How To Deceive Smart Seeds

Some seeds need help to germinate.

Plants could not proliferate as they do if they were as unintelligent as they seem to be. Actually, much of their activity would be considered quite ingenious if it could be observed in a more ‘human’ perspective. From their exploitation of pollinators to their aggressive tactics for competition with other plants, the behavior of plants is obviously very deliberate and purposeful.

Because they are so reliant on the weather, pollinators and so many other environmental factors, the life cycles of plants are on strict schedules. They must also adapt to diseases and all sorts of other pathogens. Fires and grazing animals are problems for many, but advantages to most.

Most seeds develop during summer and autumn. When they fall to the ground, they need to know to delay germination until spring to avoid frost and the likelihood of getting eaten. Seeds of many plants, particularly those from more severe climates, germinate only after being ‘stratified’ by a specific duration of cold weather. Such seeds need to be artificially stratified by refrigeration in order to germinate any differently from their natural schedule, or where winters are not sufficiently cold.

Many seeds require ‘scarification’ by digestion by animals that naturally eat them, or by the quick heat of a wildfire, to break or soften a hard outer coating that otherwise inhibits germination. Seeds that need to be digested actually rely on animals for distribution. Seed that need heat want to be the first to regenerate after a wildfire, before competing plants recover.

Goldenrain tree, and many maples and pines produce so many seeds that even if less than one percent germinate in the garden, they seem to be prolific. However, for more reliable germination of a majority of seeds, they should be scarified. The seeds of many pines that crave fire can be heated briefly in an already hot oven to simulate fire, just enough to heat the seed coat without roasting the seeds. Some people actually prefer to spread them on a piece of paper, and then burn the paper. Seeds that only need their hard outer coating to be damaged slightly might need only to be sanded lightly on sandpaper. I actually prefer to rub my canna or Heavenly bamboo (nandina) seeds on a brick or bit of sandstone.