Alan Titchmarsh: The easily overlooked factor that's the difference between a beautiful garden and wasting thousands on plants doomed to die
Planting pot-grown trees and shrubs is a quick way to create a mature-looking garden — but unless you get planting depth right, it won't last long, explains Alan Titchmarsh.
'Put the brown end in the soil, the green end above it, and you’re in with a much better chance,’ said the late Yorkshire gardener Geoffrey Smith. There is no arguing with that. The trouble is that even when following these basic guidelines there are pitfalls ahead, the most crucial of which is planting depth.
It’s many years ago now that I was reprimanded by the then curator of Kew Gardens, who was watching me plant a rhododendron. ‘Too deep, Alan, too deep.’ I learned then the perils of deep planting, and now that I garden on acid soil and I am actually establishing the rhododendrons and azaleas that were but a dream in my days of gardening on chalk, his words ring in my ear.
Rhodies, as we affectionately call them, are surface rooters; bury their rootballs too deeply and they suffocate and decline to flower. I’ve learned the wisdom of planting them so that the rootball of container-grown plants sits about an inch above the surrounding soil level. This does exacerbate the drying out of the rootball in sunny weather, but mulching the soil around the plant with chipped bark will help to reduce evaporation and encourage the exploration of those upper roots. Regular watering in times of drought — especially with newly planted rhodies and azaleas — will ensure rapid establishment.
During the hot, dry period in May of this year, on soil that is acidic and sandy, I was a slave to the hosepipe as far as my new charges were concerned. They were very quick to let me know they were short of water, as the foliage would wilt dramatically. After a good soaking, the recovery was equally dramatic: the plants picked up and bristled with health after only a few hours.
The importance of planting depth is every bit as critical for the large specimen trees that now seem to be the choice of folk who acquire a new estate and want instant effect. That option is available, of course, but at a price. Trees 10ft or more high and wide, often with a price tag in the tens of thousands, will be purchased by the dozen in the hope of creating a landscape that looks mature in a matter of weeks.
Touring one such estate a month ago, in the company of Kew’s former head of the arboretum, Tony Kirkham, we sighed over tree after tree that was struggling to survive only a few years after planting. Some were already dead, towering specimens devoid of leaf and brittle of wood; swarthy skeletons against a forget-me-not-blue sky. The cause of the problem in each and every case was deep planting.
In the same way that established trees are susceptible to changes in the water table, so trees that have been container-grown or containerised later in life are equally sensitive to a change in the level of planting. When committed to their new earth, the surface of the rootball should sit level with the surface, not 7in–11in deeper as was the case with so many of the sad specimens we saw. One can bemoan the waste of money on a tree that cost several thousand pounds, but, more than that, the loss of a formerly healthy specimen is agonising for a gardener to behold.
Why are trees planted too deeply? Probably in the belief that being tall they need greater anchorage, which deeper planting will provide. Stability is far better afforded by guy ropes that can be provided in the first year or two of establishment and removed once the tree has anchored itself. The problem is not confined to large specimens. Last week, I bought two pot-grown Japanese maples and planted them in tubs. I already have a couple that were established a few months ago. I had no reason to believe that the newcomers would not do the same, but they sulked. Then the likely reason dawned on me and I scraped away at the compost at the foot of the stem on one of them. Three inches down, I found the first root.
As rhododendrons and azaleas do, Japanese maples resent deep planting. The top of the roots that emanate from the base of the stem should be just visible on the surface of the compost, then they will romp away.
The base of the trunk or stem on any tree is recognisable, as it is generally swollen immediately above the emerging roots — the brown bit that Mr Smith told us needs to go in the soil. Let that swollen stem base be your guide and your means of ensuring the survival of both the tree and your sanity.
'Chatsworth: The gardens and the people who made them' by Alan Titchmarsh is out now (Ebury, £35).
This feature originally appeared in the June 17, 2026, print edition of Country Life. Click here for more information on how to subscribe.
