Let’s share each others point of view in tree selection and choice of trees vis a vis reasons.
Standards
Height and spread
This is probably the most important factor. Although dependent on growers choice, too big or too small mature size can be an issue. Keep in mind the ultimate height and spread of your desired tree in respect with space available and how much area you want to give to the tree. Big tree planted close to walls/buildings can lead to problem.
Growth rate
Growth rate is also very important. It should reasonably be medium to fast. or the tree will acquire its full form after your life time maybe....
Good shade
One reason of planting trees is shade. If your selected tree is not good enough to do that. What’s the use then.
Beauty
Beauty of tree comprises of three aspects:-
1) Good(your choice) foliage
2) Good(your choice) Flowers
3) Handsome structure
If your tree has nice blooms but otherwise ordinary foliage you will have to live with shabby looking tree for most part of the year as mostly flowering period of trees is couple of months. If your selected tree is otherwise beautiful but forms an uneven, lanky or dropping structure, it will be a big turn off. Selection of tree based on color of foliage, fall color, flower appearance/fragrance are one of the key selection criteria.
Beautiful canopy
This is one of the most sort after feature of ornamental trees. Trees which form round symmetrical canopies are good looking, neat, shade rendering etc
Straight trunk
Ideal trees beside canopy must have a trunk which is stable, solid looking and as straight as possible. Imagine a beautiful tree with zig zag trunk loitering everywhere. This aspect can be controlled to some extent by training the trunk and proper pruning technique.
Season of interest
Give due thought to season of interest when selecting tree. You want it flowering in spring or want to have fall color or good foliage throughout the year etc.
Evergreen or deciduous
Both types of trees have their advantages. Evergreen would mean leaves throughout but will not provide fall color on the other hand deciduous will be naked bark for at least 4 months of the year and enormous amount of litter as well.
Maintenance
Following maintenance aspects are very important:-
1) It should be reasonably disease resistant
2) Does it require regular pruning/ training, thereby increasing work load.
3) Tree should be the cause of minimum litter in terms of fallen leaves, bark and fruit. Or you would end up sweeping your lawn/beds every other day.
4) Some trees make undesirable fruit, which is not only cause of litter but also excessive bird/animal activity.
5) Ideally tree should not be the favorite tree for roosting/nesting by birds.
6) Seed germination is another major issue. Some trees have excellent germination rates. As I experienced with melia azedarach, every seed/berry that drop is sprouted if water is available. This can cause weeding issues in your borders/lawn. If unchecked you will have the same tree everywhere in your garden…..LOL
7) Root and basal suckering. This is very important aspect. Some trees send roots traveling far away and that too horizontally. This can not only damage your landscape/borders but also leech nutrients available to your other plants. Meaning by nothing left for your flowers to thrive on.
Tree Safety
Tree should be strong enough to support itself and its branches. Otherwise adverse weather will either uproot your tree wasting years of effort or branches flying here and there in high winds causing damage to surrounding area
Climatic Adaptation
Last but not the least, Very very important consideration. If you have selected a specie which is not suitable to your climate, its bound to fail. Select trees which suit your terrain/climate well so that its flourishes well.
Keep in mind what exposure (Sun-Wind-Temperature) you have at your selected site, and then select the tree. Also keep in mind hardiness zone if you are living in colder areas. Heat/cold burns, humidity requirements, rainfall/water requirement, soil requirement for that specific tree all must be accounted for. For instance tropical trees can’t survive cold areas in general, trees which require chilling period will fail in warmer areas and so on.
