Summer’s started with a bang here, 33 yesterday and 34 today. Not hot for some places but uncommon here in southeastern Victoria. I’m realising (yet again) that we don’t have enough trees. Well, enough full sized trees. There are a hundred or so small ones planted or waiting in pots, but only a handful that give shade now.
First up, evergreen or deciduous?
Shade, screening, windbreak, all the time. Things like citrus, pine, carob, olive, bay, guava, loquat, Backhousia citriodora (Lemon scented myrtle, for tea). Pines tend to be dense shade, olives lighter. Do you want a tall upright tree, leaves right to the ground or a trunk with clearance underneath? Some of your options are increased by pruning but if you’re not a fan, like me, choose a tree that naturally forms the shape you’re looking for. Some shaping when it’s young and the occasional branch removal after storms and you’re good to go.
Winter sun, summer shade, summer windbreak and screening, autumn colour. Lots more familiar fruit/edible options. (Usually more pruning too, for maxiimum fruit, specific shapes and sizes but that’s optional too.)
Apple, plum, pear, pomegranate, apricot, cherry, almond, mulberry, pistachio, walnut, peach, nectarine… Many, many choices. The size range is equally large, particularly once you start looking at different rootstocks. Apple trees start at knee height (stepovers), are commonly available around 2 – 3 metres and go up to full sized seedling grown trees. Espalier, spanish bush and spindle pruning are three ways to keep a tree small, contained and manageable. Apricots tend to be bigger trees, not taking well to dwarfing rootstocks or bendy pruning methods but they make lovely shade trees, so full size is a bonus there. Pears can be grafted onto quince rootstocks, to be half size ish – your growing conditions will have a fair bit of influence on the trees size and how long it takes to get there too. A tree planted in a warm sheltered spot, frost free and in fertile well drained soil will grow faster and stronger than one in sandy soil prone to drought and waterlogging, exposed to afternoon sun and westerly winter wind.
Things I want to know about a tree before I plant it
- Full height and width and general speed of growth – some conifers will grow 5 centimetres a year and others 1 metre. Helps to know!
- Climate preference – upper and lower temperature range, frost tolerance, does it scorch in summer above 35C (like the mystery shrubs on the driveway), can it handle 6 weeks with no rain, or 4 weeks with rain and waterlogging (because we get both, sometimes only 6 weeks apart).
- When does it lose/regrow leaves – my oaks hang onto their leaves most of winter, the the chinese elm is bare for about 4 months. This affects where you plant a tree for winter sun – it’s pretty pointless to put in a deciduous tree that drops it’s leaves only after the sun has shifted past it. Jacarandas in Sydney are one I can think of, in leaf most of winter, dropping them very early spring, then flowering, then no decent leaf cover for a few weeks as the weather heats up. Not much use on the north side of your house.
- When does it flower/does it need a pollinator – Plums are the first trees to flower here, with the Japanese varieties first, then the European a few weeks later. Knowing your frost dates, the typical last frosts and the unusual last extremes, will help if you want to choose later flowering plants, to avoid frost burnt flowers, or if you plan to cover trees. Recordkeeping is the best way to keep track of it, because you can start with the general info for your area and then map the specifics for your garden.
- Soil preference – is it really fussy about anything or will it grow most places? ‘Well drained’ is my main problem, as I have water repellent silt over clay subsoil. it’s pretty fertile once you get past the silt and the areas that are well mulched absorb water better, but the water sits on the surface and runs under it in some places when there’s enough rain. Well drained it is not. Mostly I’m working around that by digging the topsoil out of a hole, breaking up and loosening the subsoil, then filling the hole in with logs/sticks/weeds and manure to make a mound with the topsoil back on top and mixed in the top part where the plant goes. So far it’s working well. The mound sinks a little over time as the wood and weeds break down and the soil holds more water but seems to have better drainage too. Nothing has drowned yet. It’s basic hugelkulture.
- What else do I have with the same preferences for nutrients and water, already in the ground around my spot. If you’re putting in an orchard and everything will be the same kind of tree on a large scale, it’s easy to fertilise and treat trees if they all want the same thing. On a small scale it makes more sense to have trees with different needs next to each other – deep rooted trees next to shallow, full sun lovers providing some shade for understory trees, nitrogen fixers around nutrient hungry trees. Put simply, a row of apple trees will compete for the same level of minerals, water and soil space, where a mix of trees will take up slightly different niches and compete less. It’s worth spending some time planning out your space before you add new trees. Or at least thoroughly researching that shiny new tree you picked up at the nursery because it looked good!
- What can I plant around it (plant guilds). There are a few trees that really don’t like to share space and produce allelopathic compounds to discourage plants around them – walnuts and eucalyptus are two big ones. You can still find plants that will grow around them, but most trees are easier to work with. Look at the root growth (if you can find a description), ie shallow, deep rooted, tap roots, do they not mind some disturbance or will they sulk if you poke a stick near the roots? Try a mix of perennials with different growth habits under the dripline – groundcovers, grasses, upright bushy plants. You can use plants as mulch, nutrient supply and weedmat with the right choices.