In Perth with its hot climate and long summers shade is extremely valuable and becoming harder to find especially in a suburban environment. Try spending time outside your new house in the middle of summer which is surrounded by concrete/pavers and the heat can be unbearable. There is a term used for the accumulated heat from all the buildings, concrete/pavers, roads that can be significantly hotter than what the area was when it was more heavily vegetated which is known as the urban heat island effect.  

A ¼ acre block used to have at least 1 large tree in the backyard which would provide shade but it’s now rare to see. With smaller blocks trees have been cut down to make way more houses on the same piece of land or they have reached the end of their lifespan and have become diseased/pest prone and are no longer safe. 

In a small garden you really can’t go past deciduous trees/vines as they let light in during the cool winter months and provide shade throughout the hotter months. Also, there is a different point of interest for each season such as flowers followed by foliage in spring, foliage in summer, yellow/red/orange leaves (autumn) and framework of tree/vine(winter). 
Allot of deciduous plants are good also because the branches/trunks of the plants are strong, and they don’t generally drop large branches in storms and can grow in a columnar form which is upright so they can be planted closer to houses and buildings without causing damage. Also research the invasiveness of a trees root system before choosing the tree for your yard. 

Native trees can be good, and you need to check with a qualified/experienced arborist as to which are the best for planting on a small block. Small trees like Peppermints – Agonis flexuosa are good and don’t drop branches often whereas a large Lemon scented gum – Corymbia citriodora grows large and can easily drop large branches in a storm or during hot weather. On a traditional ¼ acre block they may have their place but with block sizes shrinking to 300-400m2 they are too big to be growing that close to buildings. 

Trees aren’t the only option for creating shade in a garden particular over a pergola. Chinese Wisteria – Wisteria sinensis is commonly used to provide shade in the hotter months and let light in during the colder months when it has lost it’s leaves over winter.  

 If you need help choosing the right tree for your garden we would love to help design your new garden so please get in contact.