All the fruit trees shipping off to their new homes this week got me thinking about all the holes that will be dug up and down the country as they get planted. So for all of you on the end of the shovel, this week we thought some advice and inspiration on planting trees would be timely.
By the time you dig the holes, get rabbit guards, mulch mats, irrigation, fertiliser, stakes and ties, the tree can end up being the cheapest part of the equation. But if you expect the tree to outlast you, then getting it off to a good start is a small investment. So here are some “rules” for successful planting. I’ve broken all of them, which is how I came to know them. I hope you find them useful.
The first rule of planting trees is patience. The saying goes “first they sleep, then they creep, then they leap”. Those first couple of years, especially in heavy soil, the tree is just getting it’s feet in, and nothing much happens above ground. Very frustrating for those anxious to see progress. For fruit trees, you can help by picking off immature fruit before they form to lighten the workload on the young tree while the roots establish.
The second rule is don’t plant the tree too deep. Your hole should be as deep as the root-ball of the tree. If you were buried above your neck you wouldn’t last long and neither would your tree. Plant a tree too deeply and it will rot around the base of the trunk. By all means make the hole wider and feather the roots out into it. To fill the hole, mix manure or compost with soil from the hole and pack it around the roots. Don’t use fresh manure or compost as it will burn the roots, and always mix it with soil from the hole, or it will shrink and expose the roots to air pockets.
Rough up the sides of the hole with a pick so the roots can penetrate the soil. When planting in clay the shear sides of a hole can act like a pot and the roots will grow round and round in circles. When this happens the tree can get to about 5 years old and get blown over because the roots haven’t gone out past the hole to stabilise it.
The third rule is don’t plant too close. It can be hard to imagine how big trees get when you’re planting little sticks and the “recommended” planting distances look ridiculously large but trust me, large trees are hard to pick up and move and by year 5 or 6 you’ll be wishing you planted them further apart. For small hedging and screening plants you can plant close (1.5 – 2m) and accept that you will either have to thin or will lose some through natural attrition. For fruit trees, leave at least 6-8m between trees for airflow, harvesting and mowing. For large specimen trees leave at least 12-15m between trees.
The fourth rule is mulch and weed control. Trees don’t do well with competition. Early on in my tree planting days I saw a graphic illustration of how important it is to control grass and weeds around newly planted trees. It was this photo from Appletons nursery in Nelson, a longstanding supplier of forestry and ornamental trees, that shows a series of 2 year old conifers, all planted at the same time, but with varying levels of weed control and fertiliser applied. The results speak for themselves.
If you can keep the grass and weeds down for the first 2-3 years, the trees will grow enough to shade the weeds and suppress them with their own leaf litter, or form a complete canopy if it is a hedge or shelter belt. Grass roots exude a toxin which inhibits tree growth. If you don’t control the grass and weeds in those first years, the trees will never recover and will remain spindly, weedy specimens.
Before you reach for the herbicide, there are several ways you can suppress weeds while your trees are getting established. Using a line-trimmer/weed whacker is a good one – but make sure you have tree guards on as it is so easy to mow down little trees, ditto irrigation lines. Applying a thick layer of organic mulch such as bark, sawdust, pea straw or compost is another good method. Just make sure you leave a 5cm ring around the trunk of each tree so it doesn’t rot. You can also use mulch mats around trees to do the same job. These woolen mulch mats are great because they rot away after a couple of years, just long enough for the tree to grow up above the grass and weeds.
Here is a photo of a mass planting we did some years ago along an earth bund. We used mulch mats and kept the grass trimmed back for the first 3 or 4 years and you can see the results. By year 6 a canopy had formed completely suppressing any competing grass and weeds. Hard work up front does pay off.
The fifth rule is predator protection. Skip to the next one if you don’t have to worry about possums, hares, rabbits, pukekos, sheep or cattle. There are many different ways to protect newly planted trees from being pulled out and eaten or stripped of bark. We’ve tried most of them. Spraying new plants with a mixture of egg yolk and acrylic paint did the rounds as a rabbit/hare repellent at one point. We tried it but just ended up with colourful chewed trees. There is another product on the market made out of dried blood that is also supposed to repel rabbits but we haven’t had much success with that either.
The things we know that work are guards. There are different guards for different types of tree. Here are a few that work for us clockwise from top left:
- corflute plastic tree guard – good for the first 2-3 years on little natives, but you’ve got to take them off or they’ll get muffin tops.
- wrap around trunk guard – good for hare/rabbit protection on young trunks of specimen and fruit trees
- wooden baton tubes – good for stock protection of driveway or specimen paddock trees
- mesh fencing and posts – as above but less pretty and a little cheaper
The sixth and final rule is actually 3 rules, stability, fertiliser & irrigation. If your trees are large when they go in you may wish to stake and tie them for the first year so the wind doesn’t loosen them. Don’t leave stakes on for more than a year or the trees won’t learn to stand up on their own.
Fertiliser is an optional extra. If you’re putting manure or compost in the hole you shouldn’t need extra fertiliser. You can purchase slow release fertiliser tabs for trees or just a handful of nitrophoska and gypsum will do the trick.
Irrigation is probably the best thing you can do for your new trees. If you water them once a week, deeply, for the first two summers they will get away to a good start and you should only need to water in times of drought after that.
Hope you’ve enjoyed our tour through the do’s and don’ts of tree planting. Whether you’re planting for privacy, shelter or production the rules are the same. Now all you have to do is the fun part; choose what to plant.