Landscape architects and designers often face many challenges when it comes to choosing the right tree for the right
place. So often they must perform this exercise each time they put pen to paper. To simplify the process, perhaps a
checklist of environmental conditions could be useful. The list could include tree species by climatic zone, those that
can sustain reflected sun or extreme shade, or perhaps poor soil conditions like alkalinity, salinity or inadequate
drainage, and let us not forget windy sites. Each tree species must be checked against the list of conditions to
determine if they will be satisfactory.

The check list could
include specific design criteria, such as those species suitable for use in narrow locations, proximity to pools, height
restrictions, use in containers or restricted root zones and seasonal color. Obviously, by inserting these
considerations the focus narrows considerably. We thought it might be interesting to look at a few of these items from a
design standpoint.

One of the most challenging design features today is ultimate size. With home lot sizes shrinking to postage stamp
proportions, trees used 10 years ago might seem a bit large in proportion to these yards. Designers must challenge the
plant palette to locate just the right specimen tree that does not become out of balance with the size of the landscape.
Some designers have begun using plants once considered large shrubs. These plants are particularly effective as small
stature trees especially if they can be found in relatively large containers.

From this perspective the list
of suitable species is rather extensive. Of the lesser known plants, Acacia greggii (Catclaw Acacia), Chilopsis linearis
(Desert Willow), Cordia boissieri (Texas Olive) and Vauquelinia californica (Arizona Rosewood) are just a few
possibilities.

Some professionals might think this approach to design is a disgrace to the species, perhaps bordering on 'plant abuse.'
Many arborists feel that a tree is not truly a tree unless it naturally reaches a height of 15 feet, without excessive
training. But if you review the plant palette for a climatic zone, one may find shrubs of a large stature that will
comfortably mature to the desired size, offering shade, screening and beauty.

Small trees might be convenient for use near overhead obstructions such as power lines or overhanging buildings.
Occasionally there will be CC&R restrictions that mandate maximum height limitations to maintain unobstructed scenic
views of perhaps a lake or the skyline of a valley. Such circumstances require that the designer take into account
mature height and foliage density.

On the other end of the spectrum, small properties sometimes demand petite, non-invasive root systems. Plants are often
subjected to such treatment in urban conditions. Talk about your plant abuse, this is the ultimate. Restricted root
zones, often coupled with reflected heat and glaring sun from concrete driveways and patios, presents the most
challenging design requirements. We must find plants that can withstand such harsh conditions. A short list might
include Vitex agnuscastus (Chaste Tree) Caesalpinia cacalaco (Cascalote) and Bauhinia mexicana (Orchid Tree).

When looking for trees for use in limited root areas, think of soil type and drainage. Many plants found in nature
survive in overly moist soils, heavy clay and poor water infiltration. Trees native to riparian areas or bottom lands
might be the most successful for use in confined, shallow spaces with limited aeration and drainage. Consider trees such
as Platanus wrightii (Arizona Sycamore), Platanus mexicana (Mexican Sycamore) and Salix gooddingii (Goodding's Willow)
and Salix exigua (Coyote Willow).

Trees for use near swimming pools offer additional concern. It is incredible how often one hears that palm trees planted
near a pool have caused enough damage to warrant removal. Most homeowners and some landscape designers do not realize
the relative size of a mature palm tree root system, especially species within the genera Washingtonia and Phoenix. The
narrow space between concrete block masonry walls and swimming pools is far too small in most situations for these
potentially large plants. Concrete surfaces such as pool decks are no match for the incredible force exerted by the
massive root systems. Choose trees carefully to match the site restrictions. Additionally, avoid trees with potentially
invasive roots such as willows and sycamores near water features and septic tanks. And remember, large leaves and
abundant leaf or flower litter can wreak havoc with pool filtration systems too. Some trees to consider near pools are
Acacia aneura (Mulga), Acacia stenophylla (Shoestring Acacia), Dalbergia sissoo (Rosewood) or Pittosporum phillyraeoides
(Willow Pittosporum).

While in the design mode,
consider plants with interesting features, such as attractive bark, exquisite branching systems, or flowering habits.
Many landscapers recognize these attributes and take advantage of them in the design process. For example, check out the
zigzag branch patterns of Ebenopsis ebano (Texas Ebony) or the Zizyphus obtusifolia (Graythorn). Don't forget fragrance
as a design element, with the sweet smell of grape bubblegum from Sophora secundiflora (Texas Mountain Laurel) and the
vanilla scent of the Eysenhardtia orthocarpa (Kidneywood). Fall color is a prized design factor, for which we should
consider the vivid reds and oranges of Pistacia chinensis (Chinese Pistache), many of the Oak species including Quercus
buckleyi and Q. muhlenbergii. And spring or summer floral displays abound in nature with Acacia and Parkinsonia species
as prime examples.

There are so many possibilities, just remember to keep everything in perspective. Be open minded, giving consideration
to every plant on the palette. Weigh the list of desirable features with the design constraints, gradually reducing the
list to match suitability. By finding the right associations, you are sure to find the perfect specialty tree.