Silk Tree (Albizia julibrissin) is another excellent shade tree.
OPINION
This summer has turned into quite a scorcher with higher temperatures around much of New Zealand. It is in this weather that more people recognise and value the presence of trees in our streets, parks and around our homes.
Under a tree becomes the favoured place to put the picnic rug and bask in the cool dappled shade that a tree offers. In a car park having the car under a tree will help the vehicle from being so hot on its owner’s return.
Planting trees on the west side of your house will provide shading to your abode that will reduce the solar gain and temperatures inside the home.
Talking to a passive house expert we have the example, that during the summer months windows in a home are like a heat pump, adding KWs of heat into a home.
Going further with this thought, if the heat is blocked out by a tree your house will not overheat as much on these super-hot summer days.
This is where planting deciduous trees which drop their leaves in the autumn offers so much value. They provide shade during the hot months and allow sun through during the cooler months when more solar gain is advantageous and desired.
If you ever have thought a shade tree in the backyard would be nice, then it’s probably during the hot summer days like we are having now. A tree to dapple the strong sunshine, to provide some relief from the heat, a tree to sit under and read a book or for the kids to play under without getting sunburnt.
You know that a shade sail could provide the same sun protection, but it does have not the same cooling effect as a tree.
The mass of water stored in a tree which travels from the soil into the roots, through the trunk and branches then evaporates out the leaves provides a cooling effect that is unsurpassed.
In situations where you need the tree to also provide privacy from neighbours or remove an object from view then an evergreen may be a better choice.
There is a great selection of trees that will provide excellent shade. The skill is to choose one that will meet the needs and requirements you want from it.
Things to consider are what size you would like, what space is available, would you like it to flower and would you like something with good autumn foliage colour for seasonal interest.
These need to combine along with the practical implications such as soil type, exposure to wind, frost, cold, coastal salt spray etc to ensure the tree’s successful growth.
For a smaller town section, consideration needs to be made of the shade a tree may create for a neighbour, so smaller growing or trees that respond well to pruning will make a better choice.
Cercis Forest Pansy is a stunning smaller growing deciduous tree suitable for many town gardens. Popular for its deep burgundy foliage colour, Forest Pansy can be kept tidily to around 3m tall and 3m wide providing a wonderful shade tree for a small courtyard situation. If left untrimmed ‘Forest Pansy’ will grow to approximately 5m.
Flowering Cherries (Prunus) are a very popular choice of shade tree. There are several different varieties that all have slightly different growth habits. This means if it’s a flowering cherry you want then you can usually find one that will grow to the size you have available.
Kanzan is a taller growing variety with spectacular double pink flowers and forms a vase-shaped head, while ‘Pink Perfection’ has a very similar flower but its growth habit is far more spreading so forms a better shade tree if its width you need.
Jim’s Delight is a relatively new release and only reaches 3m high. A real little gem if you want a small shade tree for a tight corner. It has spectacular single pink blossom in the early spring as well as spectacular autumn foliage as the leaves turn shades of red and orange.
A top-selling flowering cherry tree would be ‘Shimidsu Sakura’. This has an excellent spreading umbrella-shaped growth habit.
It will grow approximately 4m high by 5m wide and as well as being an excellent shade tree for the summer, it puts on a spectacular show in October with deep pink buds opening to double white flowers toned pink.
Shimidsu Sakura also had a good display of autumn colours with leaves turning tones of orange and yellow before dropping.
Silk Tree (Albizia julibrissin) is another excellent shade tree. In flower at the moment you will be able to spot them around the city with their mass of fluffy pinky-red flowers covering the trees. Hotter summers seem to improve the flowering of these trees.
The silk trees have distinctively soft ferny foliage which lends itself to providing good dappled shade from its naturally spreading branches. These trees, if left to grow, will reach approximately 6m tall and 5m wide but are easily pruned to a much smaller size. They grow quickly so good shade can be established in 3-4 years.
Driving around the city I have also seen some magnificent Jacaranda in flower with their cool bluely purple blooms, these too can be kept smaller with pruning.
Fruit trees can also make good shade trees. A plum tree at the bottom of the garden can make an excellent shade tree, with a mass of white blossom in the springtime and then an abundant crop of fruit around Christmas.
The added bonus is the fast growth rate of plum trees from which shade can be established as well as the ability they can be pruned to size – so why not make your shade tree productive and choose a plum or another fruit tree?
Other fruit trees that make good shade trees are Cherry trees, we have talked about the beauty and good growth habits of flowering cherries. You can also consider a fruiting cherry. The blossom isn’t as spectacular but the bonus of growing your own cherries is an option worth weighing up.
Evergreen shade trees tend not to change through the seasons, and apart from flowers and sometimes berries, they will offer a very similar look year-round.
If you want to use your shade tree as a year-round screen to offer privacy then an evergreen tree will be a better option for you.
A lot of the larger growing native trees make spectacular shade trees such as the Puriri, Karaka, Pohutukawa, and Titoki but in a town section these will usually grow too big for the space available.
There are some good evergreen trees for smaller and town sections. Leptospermum Copper Sheen forms a good shade tree when its lower limbs are pruned.
It has a lovely weeping habit with its coppery-burgundy red foliage making it an attractive tree. It also becomes covered in a mass of white flowers in Summer. It’s very quick growing, which makes it a good option for quickly establishing privacy. It responds well to trimming and can also be grown as a hedge.
Some Michelia varieties form lovely shade trees. I say some, because there are varieties that simply don’t grow large enough, and their habit is shrubby. However, the Dolstopa variety & its hybrids form good evergreen trees.
These varieties will form a trunk with a rounded head of branches and foliage that will offer good shade from the hot summer sun. A real feature of Michelia is an amazing display of highly fragrant, white flowers in the late winter and early spring.
So if you are feeling the summer heat, then consider a good spot to plant a suitable shade tree.
Have a good week.
Gareth Carter is General Manager of Springvale Garden Centre.
Comment: Gardening is very much about working with the seasons.