2014

 

Tree culture 

A. Climate adaptability

What suits your local garden? Obviously all trees cannot grow all places. Practically speaking, fir trees cannot grow in Florida, or Avocados in Scotland. But every area has its own range of wonderful trees and this is where the local nursery plays such a helpful role. They tend to only sell plants that are known to grow in your locale. The more knowledgeable you become of course then you will want to seek out the connoisseur or specialty nurseries, which often are mail order.


Cultural adaptability

After you have determined if a tree is suitable for your climate, ask yourself if it's suitable for the spot you have in mind. Is the ground high and well drained or does it periodically have standing water? Does it get enough light or is it under full sun all day? Is the soil rocky or sandy or have heavy clay? For all of these conditions there is a tree but all trees cannot thrive in all conditions. And you want your tree to thrive. Many trees can survive adverse conditions but they'll never reach their full potential if they haven't been placed in an optimal environment.


C. Deciduous or Evergreen

Deciduous trees are those which put on leaves (or occasionally needles) in spring and then drop the leaves in autumn and winter. Deciduous trees often have attractive flowers and/or vivid colors to the leaves in fall. In temperate areas, which are most of the US, the UK and some of Canada, deciduous trees lay bare in winter admitting what sunlight there is to light and heat your house. In summer when the sun shines hot and bright, deciduous trees are covered in leaves tempering the heat and reducing cooling bills.


Evergreens stay green year round; shedding needles or leaves only gradually. They usually lack the showy characteristics of deciduous trees, and though there are some exceptions to that, they typically have a quieter beauty about them, day after day, year round, that makes a more dignified and permanent anchor for the garden. Nothing is quite as picturesque as a craggy conifer backlit by a setting sun or a scattering of ancient yews, standing watch in a church yard. And on a practical note, evergreens make the better barrier. If you require a permanent screen for privacy or a windbreak or a noise dampener, evergreens are the best choice, whether they are yews and cypresses, or hollies and viburnums.


D. Landscape function

Ask yourself, ‘What is the tree’s role?’ If the answer is shade then choose a tree with a wide canopy. Most Deciduous trees can give shade and they can also reduce utilities. In winter they admit the warming sun and reduce heating, while in summer, they have leafed out and provide a cooling shade. But if you want a tree (trees) to create a screen then you may prefer tall dense trees, and probably evergreens. And if you simply want an attractive specimen tree, then look for foliage, berries, bark or bloom. Many fruit trees have some of these characteristics with the added bonus of fresh fruit. But a producing fruit tree deposits fruit, and where that fruit falls should be kept in mind.


E. Longevity

Trees have highly variable life spans. Often trees that grow quickly decline quickly. These are typically the over-hyped trees from magazine adverts and mail order catalogues. On the other hand, some grow so slowly that by the time they reach their full mature beauty many decades will have passed. There is a place for both of these however. Just because a tree is short-lived doesn't mean it can't be useful. Often a fast grower fills in the landscape while the more plodding, permanent tree is developing. And though screening and shade trees should be long lived, a short-lived tree may be excellent as a specimen.


F. Maintenance

Stop and think about a tree producing lots of fruit or falling leaves, like a crab apple, sycamore or oak and imagine it over a pool or driveway. And there are many beautiful trees like Paulownia or Mountain ashes, which have brittle or weak wood. Trees such as these should not be located adjacent to a house if the area is prone to ice storms and high winds. And some trees produce a lot of twiggy litter, such as Birches. If you want an immaculate lawn that can be a nuisance.


G. Pests and Diseases

Will the tree you like require any spraying because of a prevalence of certain pests in your area? Some trees have pests in some areas but not others. And some trees are bothered by canker or mildew more in some areas than others. English oaks in the southeast of the United States have a mildew problem, while in the northeast, and in the UK, a fungus has decimated elms. Make sure that whatever tree you choose, it won't be an easy victim of disease.


H. Purchasing

Always purchase plants from a reputable nursery, whether local or mail-order. While many of the giant retailers sell plants in the spring, some do not have facilities or personnel trained to properly care for plants. Ideally, select healthy, vigorous plants with leaves of normal size, shape, and color. Plants should be uniformly shaped -- free from thin spots or broken limbs. Compact, full foliage is more important than height. Examine the trunk for cankers and split bark, and the foliage for pests. If plants are mail ordered, then buy only from the most reputable. Many mail order nurseries are able to deliver healthy specimens right to your door and with guarantees for condition and survivability.


  When purchasing remember that the root system is just as important, if not more important, than the top of the plant. Check the bottom of the container for roots growing out of drainage holes. While small roots can be cut off, large roots cut in order to remove the plant from the container can adversely reduce growth. Slide the root ball out of the container to determine if the plant has become pot-bound. The root ball should stay together but be somewhat pliable. If the root ball is very hard or many roots are circling the root ball it would be best to purchase a different plant. A mass of circling roots can act as a physical barrier to root growth into the soil after transplanting. The circled roots can also choke and kill the plant as it grows. Examine the root system for small white roots along the exterior of the root ball. Do not buy plant with black roots. These roots were probably damaged by heat, freezing temperatures, excessive fertilizer, or under or over watering.


Small trees (less than 2-inch diameter trunks) do not have to look like a miniature of a mature tree. Only the bottom one-third of the trunk should be clear of branches and the foliage should be evenly distributed in the upper two-thirds of the tree. Examine the angle of the branches and avoid trees with upright, sharp-angled branches.


Small plants are easier to transplant, more economical, and adjust to transplant shock quicker than large plants, which is one reason that mail ordering can be so successful.


Large plants are more expensive, require more careful watering after transplanting, and often grow slowly for years before becoming established. This is especially true when planted on poorly drained sites where the root ball of large plants could be submerged in water.


Wind exposure during transport home can desiccate and damage foliage. Plants placed in the back of a truck should be covered. Ideally, plants should be transplanted soon after they are purchased. If there is a delay, keep the plants in a protected area and check for moisture frequently --- the root ball can dry out quickly. Excessively hot or cold temperatures can kill roots; avoid placing plants on paved surfaces that absorb and radiate large amounts of heat. The roots are more sensitive than the foliage to temperature extremes. Root injury can be expected if temperatures drop below 23 degrees Fahrenheit unless soil or mulch are used to insulate the outside of the root ball or container. If the root ball or container is left in direct sun the temperature can become too high and kill the roots. Locate plants in the shade if possible.


I. Xeriscaping

Xeriscaping is a conceptual form of gardening that uses drought-tolerant plants and grasses to beautify a home or business. Xeriscaping may become the method all future gardeners will use to develop their gardens as water becomes an increasingly precious asset to the world, especially in arid climates such as the desert. The term Xeriscape was coined by the Front Range Xeriscape Task Force of Denver Department in 1978 as a way to promote water efficient landscaping. The name Xeriscape is a registered trademark of Denver Water. The root word Xeros is from the Greek language and means dry. Xeros was combined with the term landscape (which means to modify land). [1] Xeriscape gardening is as varied and beautiful no matter the location. It does not mean gardening with only cacti, succulents and rock. It means to landscape a garden with plants that use lesser amounts of water to help people lower their water bill and reduce maintenance.

Steps


Analyze the site: The key to xeriscaping is understand which plants' needs are satisfied easily by the site, and the only way to know this is to determine what the site provides naturally, with minimal effort. Draw a map of your yard (try to keep it to scale, if you can) and gather the following information:

Make a sun chart. Find out which are the sunniest and which are the darkest parts of your site. Every few hours, record where the sun is shining on your map. Keep in mind that the site's exposure to sunlight will also vary at different times of the year, as well as different parts of the world (the sunniest part in one person's garden may still get much less sunlight than the darkest part of someone else's yard).

Perform a soil analysis. Which nutrients are readily available (or deficient) in the soil? What is the pH? What kind of soil are you working with--clay? silt? loam? gravel? All of this will affect which plants can thrive on the site. You might consider amending or tilling the soil to "jump start" the soil processes that create healthy soil, but don't try to dramatically alter the nature of the soil you're working with or else it's becoming a time-consuming, high-maintenance effort (the opposite of xeriscaping).

Study the rainfall patterns for your site. How many inches or centimeters of rain does the site get per year? Is it spread out through the year, or is it concentrated in a short, "monsoon" period?

Classify the zones: There should be three ways to classify every zone in your site:

Oasis - Close to large structure; can benefit from rain runoff and shade (which reduces evaporation, keeping more water in the soil); can also exist surrounding a large tree or at the edge of a forest/orchard

Transition - A "buffer" area between oasis and arid zones

Arid - Farthest from structures, low-traffic, receives the most sunlight

Select plants: Obtain a list of plants appropriate for your region. Use the USDA guidelines or the Sunset Western Garden book for zone information. From that list, choose a variety of plants that will tolerate drought conditions. Consult the list below for suggestions. Another way to approach it is to find out which plants are native to your area.Remember that your site should be planted in receding "layers". Think of each structure (the house, a large tree) as a focal point. At each focal point, you add a few bright, eye-catching species that are still well-suited to local conditions. As you get further away from the focal point, the plants become more subtle and also more drought-tolerant. As you're browsing lists of plants that are suitable for your area, keep these design guidelines in mind, as well as the sunniness, rainfall, and soil type of your site.

Fill large areas with a lawn substitute. The typical green lawn is a thirsty and high-maintenance "carpet". You can replace that carpet by restoring a native prairie or planting ground cover (such as a clover lawn), or you can use ornamental grasses which grow in clumps, surrounded by mulch (the idea being to only use grasses as an accent, rather than make them the major focus of the garden). The area that would normally be the lawn is usually classified as arid, so covering that area with low-maintenance plant species makes a big difference.

If the "lawn" area is so expansive that the low-maintenance plants draw too much attention, consider creating a focal point at the center. This can involve planting a drought-resistant tree or shrub, a raised bed, or a decorative structure (such as a wheelbarrow overflowing with flowers). It may require a little additional watering (try to minimize this) but at least it'll keep the site aesthetically pleasing while the surrounding area "rests" with low-maintenance species.

Group water-needy plants together near structures. Preferably, plant them in containers so the roots will get more water (rather than it seeping into the surrounding soil, where it can encourage the growth of weeds); you may even consider using self-watering pots. The pots themselves can be decorative accents.

An alternative to using containers would be to create a retaining wall (essentially a very large container), which has the added benefit of making your oasis plants stand out more.

Arrange plants based the amount of sunshine available. Some sides of the structure will get a lot more sunlight than others. Since some plants can take more sun and heat than others, plant the more sun-friendly, drought-tolerant plants where most of the afternoon sun will be located.

Develop a water thrifty irrigation system if necessary. Install drip irrigation to water plants. Water evaporation is minimized thereby saving precious water for other uses. Also, the slower you water, the less run-off there is.

Soften the boundaries. Fill the transition areas between arid and oasis zones with plants that fall in the middle of the spectrum in terms of water and sunlight needs and aesthetics. One way to do this is to create a "cascade" effect from the oasis plants (tall and bright) to the transition zone (a little shorter, catching attention by texture rather than color, such as shrubs, bushes, or ornamental grass clumps) to the arid zone (low-lying, subtle and very drought-resistant). If there is a retaining wall, however, a transition zone may not be necessary. Ultimately, see what looks best to you.

for soil retention.]]Mulch. Choose an appropriate mulch to help reduce erosion and suppress weeds. Organic, wood-based mulch will also retain moisture. As it decomposes, it'll improve the soil over time, but it needs to be replaced regularly. A stone or gravel mulch, on the other hand, does not need to be replaced, but it should be lined with landscape fabric in order to keep weeds from growing through the mulch, and it will retain a good deal of heat (which can damage delicate plants). It also attracts fewer insects.

Video


Some Recommended Plants


Shrubs

Apache plume (Fallugia paradoxa)

Barberry, Japanese (Berberis thunbergii)

Bladder-senna (Colutea arborescens)

Ceanothus (Ceanothus fendleri)Image

Cinquefoil (Potentilla fruticosa)

Cliff rose (Cowania mexicana)

Cotoneaster (Cotoneaster spp.)

Lead Plant (Amorpha canescens)

Mountain mahogany (Cercocarpus spp.)

Peashrub (Caragana spp.)

Privet (Forestiera spp.)

Rabbitbrush (Chrysothamnus spp.)

Rock Spiraea (Holodiscus dumosus)

Sage (Artemisia spp.)

Saltbush (Atriplex canescens)

Sand cherry (Prunus besseyi)

Sea buckthorn (Hippophae rhamnoides)Image

Sumac (Rhus spp.)

Yucca (Yucca spp.)


Perennials

Catmint, Select Blue (Nepeta x faassenii "Select Blue")

Claret Cup Hedgehog (Echinocereus triglochidiatus)

Curlicue Sage (Artemisia versicolor "Seafoam")

French Lavender (Lavandula spp.)

Giant Thrift-Leaf (Hymenoxys acaulis)

Hummingbird Mint (Agastache spp.)

May Night Sage (Salvia "May Night")

Pineleaf Beardtongue/Penstemon (Penstemon pinifolius)

Russian Sage (Perovskia atriplicifolia)


Trees

Burr oak (Quercus macrocarpa)

Goldenrain tree (Koelreuteria paniculata)

Green ash (Fraxinus pennsylvanica lanceolata)

Hackberry (Celtis occidentalis)

Japanese pagoda tree (Sophora japonica)

Kentucky coffeetree (Gymnocladus dioicus)

Pinyon pine (Pinus edulis)

Thornless honeylocust (Gleditsia triancanthos inermis)

Western catalpa (Catalpa speciosa)

Not all plants can be grown in all areas. Check with your local university extension, garden club or Master Gardener for more information. The information given above is from Dave's Garden and the Colorado University Extension service (see Sources and Citations below).



Tips


Install pavers intermixed with gravel, rock, or woody mulch along with Xeriscape plants.

Learn and use water conservation.

Work with a garden architect, Master Gardener or read books on gardening in your area. Xeriscaping is practiced worldwide. A Palm tree would not work in British Columbia but it may work in Phoenix, Arizona.

Plant trees and wind breaks first, then grasses and ground cover. The trees and wind breaks will provide shade and slow down wind gusts, protecting your garden.

Some favorite drought tolerant flowers include Four O' Clocks (mirabillis), Sweet William (dianthus), Moss Roses (Portulacas), and Nasturtium.

Check with your water agency and university agricultural office for more information about Xeriscaping.

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