One of the key concepts of permaculture forest gardening is that we try to use all of the different layers available to us in our forest system. The trees at the top form the canopy, these trees get the most light, water and nutrients and are often the biggest ones in the system. In order to develop highly productive systems in our backyards we need to utilise the space underneath trees to also produce for us.
The next layer under the canopy is the shrub layer. This is formed from woody plants with multiple stems rather than the single trunk common in our canopy trees. There are heaps of different functions that shrubs can fulfill — including creating mulch, forming habitat and providing micro-climates — but today we will be talking about the best shrubs you can choose when you are trying to produce food for yourself and your family.
The shrub layer can be hard to design given that the system changes as it matures. Early on, the shrubs will be receiving full sun but as the canopy matures the shrubs will start to receive partial shade. This means that either you need to change the plants in your shrub layer as the system matures (if the shrubs you chose can’t produce in shade) or you need to select shrubs that can grow in both full sun and partial shade. These top five shrubs will generally do well in both full sun and partial shade. I prefer these shrubs because I’ve noticed over the years that no one likes to cull and replant the shrubs they’ve added to the system. In addition to these true shrubs there are a number of fruit trees that can be grown or kept as small fruit trees, but we’ll save that for another post.
1. Currants (Ribes sp.), 1.5m tall x 1.5m wide
I’m not very good at narrowing down to five plants so I’ve selected currants as a general group given how well they do in a backyard system. This can include red currants, white currant, black currants as well as gooseberries and josterberries. These shrubs are hardy and start producing masses of fruit after only a few years in the ground. They generally fruit heavily around Christmas here in Australia, and my summers always had loads of red currents with sugar or honey for dessert. They can be dried and used in baking or are easily turned into cordial for consumption through winter also.
Black currents in particular are extremely nutrient dense, being high in vitamins and minerals. Further, they are extremely easy to grow from cuttings. After a couple of years you can prune off 15-25cm sections while the currant is dormant for winter. These can be placed in the veggie bed or in pots with soil and over the following year will produce roots and be ready for transplanting the following winter.
2. Feijoa (Acca selowina), 3m tall x 3m wide
I’ll declare outright that I am a Feijoa fanatic. This versatile plant can grow to a range of sizes and is easily trainable to fit into a range of situations. It can be grown in the canopy layer if trained properly but it also grows commonly as a shrub. Feijoas come from Southern Brazil and Uruguay but were brought to New Zealand over 150 years ago for cultivation. It grows readily in the sub-tropics but can tolerate minimum temperatures as low as -10°C. Also known as Pineapple guava or guavasten, it arrives in Canberra in Early autumn. Feijoas produce aromatic flowers and have a gorgeous floral display in summer of pink and red.
In New Zealand, where the Feijoa has been in cultivation for many years, there are many named varieties which produce fruit of different sizes, fruit at different times and have slightly different flavours. We’ve grown these at home for years as hedges between us and the neighbours. Feijoas have very few pests or problems and being from the same family as eucalyptus and tea-trees seem well adapted to Australian soils and conditions. In dry years they fruit less, but that said, their water needs are much lower than many other fruit trees. The skin of the fruit is edible but slightly bitter so many break the Feijoa open and scoop out the juicy insides. When baking or making Feijoa pancakes we slice them and use them with the skin on. They are also great dried and in jams.
Feijoas taste best when they are fully ripe. Let the fruit drop from the tree and you will know they are perfect. Collect and enjoy.
3. Ugni / Chilean Guava / Murtas (Ugni moliae), 1.7m tall x 1.5m wide
I was only lucky enough to discover the joys of Ugni a year and a half ago at Brogo Permaculture Gardens where John Champagne has grown it for a number of years. Following that, when I was in Chile with my partner, Ugni was everywhere. When we went to the Mapuche forest gardens of the arucarias, Ugni was in the understory.
The name Chilean guava is an indication that it (and Feijoa) are in the Myrtle family, along with guavas, and plants in this family are generally hardy and adapted to Australian conditions. The berries are a deep red with the flavor of a tart blueberry. In Chile they are wild-harvested and used in jams and also in liqueurs.
Ugni is also great in that it is easily propagated from cuttings. This means if the production drops off when the canopy starts to form shade, then you can propagate the tree and start growing it on your forest edge. People wanting to start propagating Ugni can order it from many mail order fruit tree companies in Australia. It is also sometimes sold as Tazzieberry or New Zealand cranberry but don’t let Veronica hear you call them that. They are pure Chilean.
4. Blueberry (Vaccinium corymbosum), 2m x 2m – depends on varieities
Another family bias here is my love of blueberries. My father was always telling us stories of how good the blueberries he knew growing up were, and how much he missed them. Luckily for us, the Australian and New Zealand blueberry industries started to take off and Yarralumla nursery started to propagate a number of varieties that suit Canberra conditions.
Blueberries can be slightly temperamental compared to the other shrubs in this list. They need soils that are slightly acidic but that generally isn’t an issue in Canberra back yards. We’ve used pine needles in the past to mulch around Blueberries and increase the soil acidity. They also need to be in well drained soil, but don’t like drying out. I’ve placed them in forest gardens before on mounds which allows me to vary the soil that they grow in compared with the surrounds and stop their feet getting too wet.
5. Goji Berry (Lycium chinense and L. barbarum), 1.2m tall x 1.2m wide
Goji berries are extremely popular at the moment and supposedly have a range of life-giving properties that will allow you to live to 100yrs old. They are also extremely delicious and practically grow themselves so they are a great candidate in the shrub layer. Originating in China, Goji berries are in the tomato family and are sometimes sold at nurseries as wolf-berries. The red-fruits they produce dry really well and so are great for year round eating. In China, a tea is commonly made with the berries, but I love them in cakes and cookies.
Goji needs more sun than the other shrubs mentioned here to produce heavily, but again it grows easily from cuttings. If the shade gets too deep it can be propagated somewhere else. These are generally available at the nurseries around town or in the mail. My first one was savaged by a possum but it grew back and now is thriving. If you buy dried Goji berries it can sometimes be germinated from seed.
So there you have it, five shrubs for the backyard food forest garden. If these shrubs don’t seem particularly abundant remember that the plants in a food forest are sharing resources and we generally want our canopy trees to receive the most resources. The shrubs generally help as suppourt (mineral acquisition, bird habitat) so anything else is a bonus. I’ll cover more utility shrubs and small trees in the next post. Happy Forest Gardening.