Bare-root tree planting: how and why

Crab apple, meet garden

It's been damp, so I'm working off planks here

January has been a month of waiting! I promised myself a crab apple tree once a freelance writing client had paid their invoice, and when they did I let out a whoop and headed straight to shopping. I feel thoroughly middle-aged about this, and also gleeful that middle age turned out to be fun after all.

I love crab apples. They're great for wildlife, they're beautiful all year round, you can often make jelly from the fruit, and they come in small-garden-suitable forms. 

This lovely purchase is not only a big step forward in transforming my formerly boring new-build garden, they're also a nice opportunity to demonstrate bare-root tree planting for any of you doing the RHS Level 2 certificate in Practical Horticulture. So here's a runthrough. 

Methods for this, like many gardening tasks, vary widely, and there's more than one technique for successfully planting trees. Some people get het up about this and argue with each other about whose way is 'right'. I'm not saying my method is The Method - but since this blog is primarily to help RHS students, the process I set out here is the one I was taught at Capel Manor.

This project was supervised by Polly.

Planting a small bare-root tree

When to plant bare-root trees

Bare-root plants are only available from October to March, which is also their planting time. If you're an RHS student, this means bare-root planting is not likely to come up in your June practical. But it may appear in the March one!

Plant when the ground isn't frozen. A frost after planting doesn't really matter. You just don't want the roots to get frozen on the way in, and you need soft earth to get the tree in properly.

Sourcing the tree

You can order bare-root trees from an online supplier, or pick them up from a local nursery that stocks what you need.

I'm on a tiny budget and went for the one I could afford that had the best reviews. Sadly that wasn't Malus 'Jelly King', which I fancied but which was out of my budget. I plumped for a Malus 'Evereste', also a good fruiter and suitable for a small garden, from Roots. Nice, short delivery time, mostly good reviews, decent price.

Excuse the mess.

Storing the tree

I kept my new twiggy friend in the box in my nice frost-free, mouse-free shed from Wednesday to Saturday. I did moisten the roots and wrap them in  a plastic council recycling bag. The note from Roots said "don't worry if the roots are dry, they're dormant". Maybe this would've been fine, but everyone else, including the RHS, advises keeping them moist. As I only had one tree, I wasn't taking any risks.

Had it been a longer wait, I'd have 'heeled in' the tree. This means popping the roots under a thinnish layer of compost, usually in the ground at a 45-degree angle. You can also put it into a bucket of moist compost in the shed.

You will need:

• Bucket of water
• Spade
• Fork
• Mycorrhizal fungi/Rootgrow (optional)
• A post driver, a sledgehammer or mallet (see Staking, below)
• Straight plank, metre stick or similar straight item
• Tree stake - should be about 1/3 the height of your tree
• Super soft rubber tree tie
• Rubber spacer
• Tree guard or spiral
• Mulch
  
  
  
  Roots soaking in a bucket.

Before planting

Look for a nice, clear top leader (main branch) and check the general health of the tree before putting it into your garden. Also check that the ground isn't frozen. 

If you're ordering a bare-root tree for the first time, you may get confused about how long to soak it right before planting. Opinions vary wildly from 2 to 72 hours! Some say oversoaking 'suffocates' the roots, others say soaking for at least 24 hours is vital to ensure the tree can thrive. 

Roots, the company I bought this tree from, don't seem to be sure internally. Two days before delivery, I got an email telling me to soak the tree for 24 to 72 hours before planting. Delivery day was forecast to be freezing and Storm Eowyn was due to hit, with 90mph winds, two days later. So I decided to just moisten the roots, keep the tree in its box in the shed for a few days, then soak it for a few hours and plant it after the storm.

When the tree arrived, there was a note in the box telling me to do just that! I messaged Roots, and they did say the note contained outdated info, so it sounds as if they're now recommending a longer soaking period. There are some tasks in horticulture that no matter how you do them, someone will consider your method to be wrong, and this is one of them. Think about the conditions and the specific tree you have, and go with what works for you.

Anyway - I'm happy with the tree itself, it looks fine and has an OK rootball, and in the end I just applied common sense. Roots maybe need to work on their instructions, though!

Planting the tree

Identify the prevailing wind. In my garden, it's southwesterly.

Identify the root flare of the tree. Look for a bulge just above the roots. There might also be a muddy mark here where the tree was previously planted.

First level the ground.

I used an old meter stick as a level.

Next, dig a hole to a spade's depth, 9 times the size of the rootball. If you're feeling really perfectionist, you can make different piles of organic layer, topsoil and subsoil so you can put it back in the same order. My soil has been dug over fairly recently, so I didn't bother with this.

Fork the edges of the hole, NOT the bottom. You want to encourage lateral (sideways) root growth for stability.  

Level the bottom. Don't add any organic matter. You want the roots to go seeking nutrients, so the tree establishes - that won't happen if you provide everything it needs right where it's planted.

Use your straight object/plank to check the level of the root flare against the surrounding soil level. You'll want the flare to be just under the soil. Deep planting is not good for trees, so be precise about this.

Because I have clay soil, which holds water and is dense, I used the 'octopus on a hill' method. You make a mound at the bottom of your hole for the tree to sit on - making sure the root flare is still at the correct level. If your tree's roots are long enough, drape them over the mound like the tentacles of an octopus. This helps your tree to establish in heavier soil. 

You can also apply mycorrizal fungi. This isn't vital, and opinions differ on whether the fungi available for sale in garden centres is actually specific enough to be useful. But I had some, so I sprinkled a bit in and mixed a bit more into the pile of extracted soil. 

Staking the tree

Mark the stake 40cm from the bottom with a pencil.

Insert your stake at a 45-degree angle, avoiding the roots and pointing into (not with) the prevailing wind. Mine points to the southwest.

Lightly push it into the ground so it won't fall over. Now it's positioned, you can cover the roots. Backfill soil into the hole.

You can use a sledgehammer, mallet or post driver to drive the stake at least 40cm into the soil (your pencil mark will help with this). You might need help for this, and anyone whose head is below the top of the post must wear a helmet! If the soil is soft, you may get away with a mallet.

The stake should allow the tree to sway slightly, but not fall over. 

Use a super soft tree tie to attach the tree to the stake, about 40cm up from the soil level. This can be fiddly, so for RHS exam purposes I recommend practicing with one at home - they're only about 50p! You'll also need a rubber spacer, which stops the stake from rubbing against the trunk and debarking the tree.

For home purposes, you can also get away with using a piece of rag as long as it's soft enough not to rub the bark, and knotting it to make a spacer. We didn't always have rubber plastic, after all. 

This staking method is great for a small tree, up to a couple of metres. Taller or very broad trees will need more support.

Finishing touches

Firm the soil with your foot, adding more if necessary.

Adding a spiral guard protects the tree from rabbits, deer and even mice. Any creature ringbarking (eating around) the trunk will kill it.

Mulch the area in a 5cm layer, leaving a 10cm clearance from the trunk. Mulch touching the trunk can cause rot, and you don't want that.

Admire it!

Aftercare

Water the tree regularly for the first couple of years. Mulch it again every year, and apply any specialist care (such as feed) that your particular tree needs.

Regularly check your tree tie - every six months if you used a rubber tie, more often if you used cloth. Loosen it if it gets too tight, replace it if it breaks.

You'll need to keep the stake in place for two to three years.