Planting trees

 

At Westonbirt we plant our new specimens once the mad rush of autumn is over and the trees have shed their leaves and shut down for the winter. Over the years, with a bit of trial and error, the Westonbirt team has developed its own particular method of planting and protection that gives our valuable young trees the best chance to thrive.  As with many activities, the mass of anecdotal folklore and old wives’ tales can make the job seem a lot more complicated than it really is.  Like cooking, if you start with good ingredients (healthy plants), follow a few rules and keep things simple, anyone can plant a tree successfully.  Of course, there’s no substitute for selecting the right plant for the site and good planting technique won’t make-up for an unsuitable soil type or location.  But plant selection is too large a subject for this page and there are plenty of books on the subject.

Trees are usually bought either as container-grown (purchased in a pot) or bare-rooted. The former is much more common, particularly for domestic trees and allows planting to be carried on regardless of season – with close attention to watering. The following guidance does not deal with the question of staking or other means of support as at Westonbirt we prefer to avoid using them wherever possible by using small plants. Trees up to about 1.2m (4feet) in height with a good root ball should not need staking and will generally out-perform and overtake larger ‘standards’ despite their lower cost.

Digging the hole

There are many debates about how large and what shape of hole you need to dig.  This varies a bit depending on the nature of the soil - in a good, crumbly loam it need only be slightly wider and deeper than the pot size or bare root spread.  On poorer, compacted soils it’s best to give the tree a bit of a helping hand by digging a hole up to twice the pot diameter or root area. Some people maintain that a square hole is better than a round one on the theory that the corners encourage the roots to venture from the comfort of their pot area and develop quicker.  I’m not convinced but give it a try – it can’t do any harm.  Whatever shape or size you dig, the important thing is to get the correct depth - a point dealt with under the next heading. 

Some people believe in adding compost to the hole at this stage before planting and mixing more into the back-fill soil.  We do not do this and believe it unnecessary on all but very poor sites.  Most garden soils have a structure and nutritional level quite sufficient for tree growth without fertilising or other improvement.

From pot to ground
Plants should be carefully removed from the container so as not to disturb the roots.  If the compost is very dry, it should be thoroughly soaked and left for about an hour.  Most planters recommend ‘teasing’ the fine roots around the sides and bottom of the compost to encourage them to spread. Don’t be too enthusiastic though! 

The next stage is important and one that it’s worth spending a bit of time on.  Placed in the hole, the top of the pot compost should be level or just above the ground at the sides of the hole.  On bare-rooted trees with no compost, it is the level of the root collar (the line where root becomes stem) that is important.  You may have to adjust the level by adding or removing soil to the hole to get this just right.

Back-filling
The important thing here is to compact the back-fill soil around the tree enough to make it wind-firm and remove large air pockets.  But care is also needed to avoid damage to fragile roots with large booted feet!  I find it best to return the soil a-bit-at-a-time, compacting at each stage.

Mulching

The main purpose of mulching young trees is to prevent drought stress and reduce the need to water.  This is achieved directly by reducing evaporation from the surface and, more importantly, by suppressing weeds that compete for moisture.  We use bark chip rather than the special textile sheeting as we find the latter to be too long-lasting and requiring maintenance.  Bark mulch should be applied to form a circle about 1m across and to a depth of 50mm (2 inches) leaving a small space around the stem.

Protection

Guards, cages, shelters and tubes come in a variety of shapes and sizes depending on what they are there to protect the tree from.  We use short cages to protect from rabbits and 1.2m (4ft) ones for roe and other deer.   Whatever you use, remember they need to be regularly maintained to prevent them damaging the tree they are intended to protect.

So that’s it – just the weeding, watering, pruning and checking to do for a few years and you’ll have a great tree!