Page 9 - Simply Vegetables Winter 2020/21

Success with ‘Little Trees’
Putting the M27 to the test
ADRIAN BAGGALEY
Several years ago my wife passed me a request from her best friend Janet. “Janet wants some ‘little trees’, after some qualification this was confirmed as four apples, growing no more than 5-6ft tall (152-182cm) and with a minimum spread across the lawn.
This request gave me the opportunity to try out the much maligned M27 rootstocks. For anyone not familiar with the Malling rootstock system, M27 is the most dwarfing and is not recommended by many people, amateurs, growers or nurserymen alike. The challenge was to grow diploid varieties of apple grafted on to this rootstocks, to plant them in a lawn, the ‘soil’ being heavy clay, and to produce a worthwhile crop of fruit.
Around this time a friend grafted me two vigorous varieties onto M27 Blenheim Orange and Winter Gem (the first being a triploid). I will come back to these later.
Year one, autumn. The four trees were selected: Saturn, Winter Gem, Limelight and Red Devil. My advice was to grow them in my favourite method of restricted form, i.e. dwarf pyramids. My instructions were to dig out a hole for each tree, around 3ft (91cm) across and as deep as their energy would take them, to throw away all the spoil, and to back-fill with a 3:2:1 mix of top soil, peat and sharp sand, how far they went with all this
is uncertain, but four apples (and two pears) were duly planted in the lawn and staked securely*. I pruned them back to around 20in (50cm) high and took off most of the ‘feathers’ (side shoots); any feathers left on were pruned hard back. Early spring, the trees were given a sprinkling of Growmore. Instructions were left to mulch with grass- cuttings in late spring, and to water regularly
through to September.
Year two. I vaguely recollect pruning the
trees in the winter and hearing the sighs and groans the next spring as I pinched out the blossom. I think Janet and family were so disappointed they didn’t ask me back for years.
Several years later I was asked to go back to ‘...have a look at the broken branches...’. This, I discovered, was a direct result of the lack of formative pruning, and over-cropping. But the point is - the trees had cropped, were still cropping, and cropping magnificently. This I put down to the precocity of the rootstock, the initial husbandry, the friable planting medium which got the roots away, and ongoing watering through the growing season.
Based on this experience, I think M27 rootstocks, unjustifiably, have been given a bad name - probably because people plant them and walk away, leaving the trees to get on with it (I agree – Ed).
As can be seen by the pictures the trees were a success and would have been
even better had there been more formative pruning, Formative pruning in the winter period results in a more compact tree with less or no blank parts. Also, more summer pruning, year-on-year, would have also have created a more compact tree with more fruit buds, a ‘fruit factory’. I should point out that contrary to the picture, the variety Red Devil is a most regular and prolific cropper, (I think the one in the picture had been cropped) It is my number one show variety. The Winter Gem is a really great tasting and good looking apple, but an uncertain cropper, for that reason the Winter Gem was taken out recently.
Red Devil
Now back to my two varieties: Blenheim Orange and Winter Gem. It is quite evident, in my experience, that triploids, and the more vigorous cultivars, usually require the next root stock down, if not two rootstocks down, from the rootstock that you would normally choose for a diploid cultivar in
a given space. A vigorous cultivar on the wrong rootstock can produce lots of lush growth and little fruit, or fruit of poor colour. John Scott, the founder of Scott’s Nursery always said ‘fruit not faggots’ (i.e. grow trees to produce fruit not timber) and that is as true today as it was in his day. This is what
I set out to prove by trialling the vigorous Blenheim Orange and Winter Gem on M27 rootstocks.
My Blenheim Orange on M26 rootstock seldom has good colour, definitely not living up to its name - last year the same variety on the M27 was nicely coloured up, but the M26 tree had green fruit. The same went for the Winter Gems: on M26 poor skin colour, on M27 nice colour. My theory on skin colour is that the harder you work or handicap
the tree, the better the colour - a dwarfing rootstock effectively makes the variety grafted onto it work harder - you are giving it more to do, due to the restriction on vigour.
I am so exasperated by the poor quality fruit of the M26 Blenheim and Winter Gem that they are coming out.
So ignore the bad press given to M27
- give both diploid and triploid varieties a
go on this much maligned rootstock, plant some in the lawn or the flower beds and give them some TLC - you will be surprised at just how good M27 trees can be.
*Note: because of the root system produced by M27, varieties grafted onto M27 must be staked for life.
This article first appeared in the RHS Fruit Group Newsletter in 2015.
Limelight
Saturn
Simply Vegetables 9