Choosing Trees

Mountain Ash, Fall colour

Once the final plan for the garden is settled upon, trees can be one of the first items planted. The sooner their roots are in the ground the sooner they will be on their way to maturity.

Maturity; regardless of whether you plan on being in the house for two, twenty of forty years, it is a good idea to plan for the mature size of the tree. In show gardens and some parks, trees will be planted and kept until a specified size, purely for visual effect, then removed but that is really not practical for a home garden. Trees have a predetermined height and size so planning for that is of crucial importance. There is nothing more beautiful than a mature tree, even though you may have to wait awhile to see it. Some trees grow faster than others, another factor to be taken into consideration.

It grieves me when I see trees topped because they were not planned for.  Nothing will stop a tree from reaching its mature size and when it does, its girth will be the only part of it to increase. It is far better to plant the right tree in the right place than having to keep pruning it badly by topping it. When a tree is topped the leader is cut off. This stimulates water sprouts to take its place and numerous small branches will begin to grow straight up to reach that predetermined height. Its shape will be lost and the tree will need constant pruning to keep a shape, whereas if a tree is left to grown naturally it will attain its predetermined beauty and shape.   Trees will need occasional pruning for tidying purposes but not a great deal if the tree is appropriate for its space. ‘Raising the canopy’ is often needed when an immature small tree is planted. As it grows the lower branches can be pruned off to make more headroom for walking underneath. Crossover branches and dead branches might also need to be removed but this very different than cutting off the leader trunk at its top. Fruit trees are another story again if they are to be kept to a manageable height in order for fruit to be picked. Large shade trees and ornamentals need to be selected carefully in the first place.  Their maintenance should be minimal and their leaders should be left.  

Good consideration needs to be given to this more substantial plant purchase. The document in this link is a resource I put together 20 years ago for Cranbrook BC. Not much has changed in twenty years although there are some new varieties to be considered. This resource is for street or large trees only. It does not contain fruit trees or small ornamentals. We will come to those lists later. The format is primitive but the information is there and as many of the photographs as possible were taken in the Cranbrook area.

I have to put in a plug for the Linden, Tilia. It is the toughest large tree I know for this area that has a beautiful shape and wonderful fragrance when it flowers in late June-July. What the small yellow flowers lack in noticeability they make up for in fragrance.

A large garden tree will serve many purposes and is one of the most valuable additions to the garden. It will provide:

Shade

Habitat for wildlife

Leaves for composting

Cooler temperatures

Oxygen

Rustling sounds

Screening from neighbours, roads, noise

Beauty in form and sometimes fragrance

Dimension, colour and texture

Height that no other plant can and a potential

Framework for a hammock or swing.

Here is the link to Trees for the Cranbrook Climate and also a downloadable file. Both are the same document. They are of course suitable for any climate hovering around zone three. Planting directions are also provided in this resource and as mentioned before in another article the addition of mycorrhizae is now recommended. Known commonly as ‘Mike’ this will foster strong root development and is available at time of tree purchase. This document is now public property so you are welcome to download a copy.

The following list does not include small ornamentals.  All the trees will attain a height of at least 5m (15ft).  The list was compiled after consulting numerous sources (see full document for complete list of references) as well as my own growing experiences. The majority of the photographs were taken in Cranbrook, B.C.  Within many species or hybrids there are named cultivars or varieties, which demonstrate small individual characteristics.   For example under Aesculus x carnea the variety ‘Ft. McNair’ was named because it is considered hardier than other red flowered varieties.

Contained within this resource are:

Acer ginnala                                               Amur or Ginnala Maple

Acer negundo, varieties                           Manitoba Maple or Box Elder

Acer platanoides, varieties                      Norway Maple

Acer x freemanii                                         Red Maple

Aesculus glabra                                           Ohio Buckeye

Aesculus x carnea ‘Ft. Mcnair’                Red Horse chestnut

Amelanchier x grandiflora                       Saskatoon, Serviceberry             

Celtis occidentalis                                Common Hackberry

Crataegus x mordenensis                         Hawthorn, Mayflower

Eleagnus angustifolia                                Russian Olive

Fraxinus manshurica                                 Manchurian Ash

Fraxinus nigra                                        Black Ash

Fraxinus pennsylvanica                         Green Ash   

Malus baccata or Malus x                        Crabapple

Picea pungens                                         Colorado Spruce

Populus species and hybrids                   Poplar, Cottonwoods, Aspens

Prunus maackii                                          Amur or Manchurian Cherry

Prunus padus                                             Mayday

Prunus virginiana                                     Schubert Cherry, Common Chokecherry

Quercus macrocarpa                                Bur Oak, Mossycup Oak 

Sorbus aucuparia                                      European MountainAsh, Rowan

Sorbus Americana                                    American Mountain Ash

Tilia cordata                                               Linden, Lime, Littleleaf Linden

Ulmus Americana                                     Elm