The October Garden 2022
October already? What happened to the rest of the year, I hear you saying! As we enter the middle part of autumn the hot, dry summer seems like a distant memory after the rains at the beginning of September and we can start to look forward to all the delights that autumn has to offer. There are plenty of flowering plants still gracing our gardens including the autumn specialists- Aster (some of which are now called Symphyotrichon), Caryopteris, Chrysanthemum, Helenium, Helianthus, Leycesteria and Schizostylis just to name a few from our own garden. In addition there are the golds, yellows and light browns of seed heads from flowering plants and grasses as well as the gloriously faded colours of Hydrangea flower heads.
However, in October our eyes also begin to turn to the first hints of colour on the leaves of perennials, shrubs and, perhaps most of all, trees, and for this reason this month’s blog will concentrate on trees in general, fruit trees in particular and to tie in with the Old Railway Line’s Apples and Cider Festival on the 8th of October will focus on the apple tree.
Trees are truly wonderful and amazing living things and I for one can’t imagine living in a place without them. They are generally described as long-lived, woody perennials, deciduous or evergreen each usually with a single stem or trunk (although some can have two or more trunks from the same root system) and an often intricate branching system. The trunk generally tapers towards the top and is clear of branches in the lowest section- the bole. They differ from shrubs in that shrubs tend to be smaller and have several stems that branch from near soil level. Trees range in height from dwarf conifers less than 1m (3ft) to giant specimens such as the Coast Redwood, Sequoia sempervirens, up to 90m (300ft) high. Being much taller than most other plants means that trees not only need to be strong in order to support their considerable weight but they also need to move water, nutrients and sugars vertically over impressive distances. To do this between root tips and tree tops they, like all vascular plants, use two types of transport vessels- xylem and phloem. The xylem transports water and soluble nutrients from the roots upwards throughout the plant and works partly by capillary action along thin tubes but also by a ‘suction’ process that is produced by the transpiration (evaporation) of water from the leaves pulling water upwards. This transpirational pull can lift water hundreds of feet to a tree’s highest parts and in the right conditions can move the water remarkably quickly- up to 8m (26ft) per hour! Phloem vessels transport a solution rich in sugars, amino acids and hormones in both up and down directions throughout the plant due to a process called translocation which is not yet fully understood. One theory is that the phloem sap moves from areas of high concentration to areas of lower concentration in the same way that air moves from areas of high pressure to low pressure.
A Yew and a beautiful Purple Beech at Aberglasney // Tree views from one of our upstairs windows
For gardeners trees form the largest and most prominent of all garden plants and establish the basic, long-term framework of any garden giving it a sense of permanence and maturity and linking it through other trees beyond the garden boundary to the broader, external landscape. They add height, structure and focal points while their distinctive silhouettes form an attractive contrast with the softer lines of other plantings. There is an enormous variety of garden trees offering different sizes and shapes as well as the colour and texture of foliage, flowers, fruit and bark. They can also be used in several different ways for example as specimen trees in a lawn, in a large shrub border as a focal point, in pairs to mark entrances or to frame a view, in rows or groups to mark a boundary, as hedges, for topiary and to provide shade both for garden users and other plants. More recently we have all become much more aware of the vital role that trees play in improving the environment in general. Through the process of photosynthesis they absorb and lock away carbon dioxide and release oxygen, they protect the soil from erosion and help to reduce and slow down surface water runoff and they provide a safe habitat and a vital food source for many insects, birds and other animals. For all these reasons we have rightly been encouraged to plant trees in our gardens as well as in the environment in general and I am sure that many of us have made a recent addition to the total tree count as part of the Queen’s Canopy planting programme. I for one can’t think of a better way to honour and remember our late Queen than by continuing to plant more trees wherever we can.
If you haven’t got room for full size trees why not try bonsai as I do?
Moving on from trees in general to fruit trees in particular let me just mention briefly the different types of fruit which gardeners can grow. Trees come in the group known as ‘Top Fruit’ which includes both ‘pome’ fruits which have a core with pips/seeds (Apple, Pear, Medlar) and ‘stone’ fruits (Cherry, Peach, Plum). There are also some tree fruits in neither of these groups including Fig and Mulberry. A second fruit group is ‘Vine Fruit’ which includes the woody climbers such as Grape Vines and Kiwi Fruit. The third group is the ‘Soft Fruit’ which can be sub-divided into:-
‘Bush’– shrubby and compact such as Black, Red and White Currants and Gooseberry
‘Cane’– cane-like shoots which usually grow one year and fruit in the next year such as Raspberry, Blackberry and hybrids such as Loganberry and Tayberry
‘Strawberry’– herbaceous plants spreading by runners (stolons)
Most tree/top fruit and certainly Apples (Malus) can be grown in different forms- natural shapes or trained shapes. Natural shapes are generally referred to as ‘Bush’ with a trunk around 1m (3ft), ‘half-standard’ around 1-1.5m (3-5ft) and ‘standard’ 1.5-2m (5-6ft) high all with a rounded head of branches adding another 1-1.5m (3-5ft) in height. Trained shapes take the form of ‘Cordons’ which have a single stem 1.5-2m (5-6ft) long planted at an angle of 45 degrees, ‘Fans’ whose main branches radiate in a fan shape from a short trunk against a wall or fence, ‘Espaliers’ which have matching pairs of horizontal branches at intervals along a central, vertical stem also against a wall or fence, ‘Step-overs’ which have a short stem and just one pair of horizontal branches around 30-45cms (1-1.5ft) above the ground and ‘Pyramids’ which are free-standing shapes wider at the base than the top.
Apples (Malus sylvestris var. domesticus) are a very interesting (as well as tasty!) fruit in that for flowering to occur the tree must have at least 900 hours (equivalent to 50-60 winter nights) per year below 7 degrees Celsius, known as the chilling requirement, so cannot be grown for fruit in tropical and sub-tropical regions. In the UK, however, lack of chilling is not a problem but with our sometimes cool and cloudy summers it is best to grow apples in a sunny and sheltered spot for the best crops.
The different shapes noted above are produced and maintained by the various pruning methods mentioned later in the blog but the overall size of the tree is controlled more by the root stock on which it has been grown. Most tree fruit and certainly apples are grown by grafting some part of a good fruiting variety onto a strong growing root stock. The two main methods used are firstly ‘bud’ grafting where just one bud from the scion or bud stock in mid-summer is grafted onto a root stock. In the late winter the following year the part of the root stock above the graft is removed and the new top then grows away to produce a single stem known as a maiden. This will in time produce side-shoots and develop into a bush shape. A second type of grafting known as ‘whip and tail’ is carried out in mid-winter just before bud break which uses of a scion about 9 inches (20cm) long with at least three buds along it which is grafted on to the top edge of a root stock from which all side shoots have been removed. It is the vigour of the root stock which will determine the final size of the tree and there are several root stocks now available for apples. These are all prefixed by M or MM (Malling and Malling Merton) which are research stations in Kent where the root stocks were developed. These include:-
M27- very dwarf 1-1.5m (3-5ft)
M9- dwarf 2m (6ft)
M26- small tree 3m (9ft)
MM106-medium tree 4m (13ft)
MM111- large tree 4m+ (13ft+)
With all tree fruits including apples there are several considerations which the gardener needs to take into account when deciding on what to grow and where. Firstly the space available will determine what can be grown as well as how it can be grown. In larger spaces it may be possible to grow several trees in an orchard style, in small spaces one tree on a dwarf root stock might be the best choice and in even more restricted spaces trained trees might be more suitable. Tree fruits other than apples also have different root stocks available. Pears are grown on either Quince C (3m/9ft) or Quince A (4m/13ft), Plums/Gages/Damsons are grown on Pixy (2m/6ft) or St Julian A (3-4m/9-13ft) and Cherries are grown on Colt (4m’13ft) or Malling F12/1 (5m/16ft).
A second consideration is concerned with pollination. Many fruit trees are self-sterile (they cannot pollinate themselves) and therefore require another tree of the same type (apples cannot be pollinated by pears!) nearby and flowering at roughly the same time. Apples come in seven flowering groups which overlap to some extent so that, for example, a group 4 flowerer will pollinate and be pollinated by a tree from groups 3, 4 or 5. Even self-fertile varieties, of which there are a number, crop more heavily if other pollinators are present nearby. If there is only room for one tree a possibility these days is to grow a ‘family’ tree on to which two or three different varieties have been grafted which will pollinate each other. Otherwise the gardener can look for help with pollination by relying on trees in neighbouring gardens from either crab apples or fruiting trees as pollinating insects do travel quite long distances in their search for pollen and nectar. One complication which I have to mention, however, is that although most apples are known as diploids which will happily pollinate other diploids as long as their flowering periods overlap a few varieties are known as triploids which will not pollinate other trees. If a triploid is grown then at least two diploids are needed in order to pollinate each other and the triploid. For the amateur grower they are probably best avoided unless the variety is a particular favourite. The best known triploids are in dessert apples ‘Jonagold’,’Jupiter’ and ‘Suntan’ and in culinary apples ‘Bleinheim Orange ‘and, unfortunately perhaps the best loved cooker, ‘Bramley’s Seedling’.
Finally in order to create a strong framework of branches and to produce the best crop possible the correct pruning methods and timing need to be used. Initial pruning and training will have been carried out in the tree nursery prior to purchase and if unsure about how to continue this it is perhaps best to learn from an experienced hand. Failing that there are plenty of books on the subject most with excellent diagrams and these days there are also many YouTube videos available. In this final section I will endeavour to get you started with some basic points about pruning apples.
Apple trees produce flower and fruit mainly on two-year old and older shoots. These carry both larger, plump fruit buds and smaller, pointed growth buds. Fruit buds produce flower clusters and then fruit if pollinated whereas growth buds form into side-shoots (laterals) and tip shoots in the current year or fruit buds in the following year. One of the main purposes of pruning is to encourage the formation of these fruit buds for increased cropping in the future. It is also important at this stage to know whether the cultivar being pruned is a ‘tip bearer’ or a ‘spur bearer’ so that the appropriate method of pruning is used. Tip bearers as the name suggests carry most of their fruit buds and therefore the crop at, or near, the shoot tips and it is vital that these are not removed during pruning. Popular tip bearers include in dessert apples ‘Discovery’, ‘Lord Lambourne’ and ‘Worcester Pearmain’ and the culinary apple ‘Bramley’s Seedling’. Spur bearers, which form much the larger group, bear flowers and fruit along the whole length of a shoot on short-jointed spurs which are essentially side-shoots. Pruning of these cultivars involves the shortening of both main and side-shoots to encourage fruiting spurs to form.
The pruning of trained trees ie. cordons, espaliers, fans, step-overs and pyramids is carried out in the summer once the young shoots have become woody at the base in order to reduce the amount of leaf growth, allow more sunlight to reach the developing fruit and to keep the tree within its allocated space. Basically all new laterals/side-shoots more than 9”(20cm) long that are growing along the main stem or branches are reduced to three leaves above the basal cluster of leaves. Secondary side-shoots from the main laterals are pruned back to one leaf above the basal cluster.
The pruning of bush trees including standards and half-standards is carried out in the winter when the trees are dormant between December and February. This stimulates new growth in the spring which in the following years will produce new fruiting buds. It is important to remember that the harder the pruning the more vigorous the regrowth so it is important to know something about the vigour of the tree being pruned which is partly due to the cultivar and partly with the root stock on which it is growing. Vigorous growers need light pruning otherwise they will put on too much new growth whereas less vigorous trees require more pruning in order to encourage the formation of new side-shoots. The most vigorous growers include in dessert apples ‘Jonagold’, ‘Jupiter’ and ‘Suntan’ and in culinary apples ‘Blenheim Orange’, ‘Bramley’s Seedling, ‘Howgate Wonder’ and ‘Newton Wonder’.
To finish on the subject of pruning I would just like to comment on two very commonly asked questions in garden centres. Firstly why do some fruit trees, especially some apples, plums and pears, crop well one year and then produce very little, if any, fruit the next year? This is known as biennial cropping or bearing and is connected to the health of the tree, the vigour of the cultivar and environmental conditions to do with the soil and weather. In an ‘on’ year, producing lots of fruit places such a huge strain on water, nutrients and energy supplies that the tree takes the whole of the next year to recover. It is possible to try to break this cycle when pruning in the winter following an ‘off’ year by leaving on the tree as many one year old shoots as possible ie. unpruned. These will not produce fruit in the next summer, the ‘on’ year, but will go on to produce flower buds for the year after ie. the next ‘off’ year. A second question often asked is about ‘water shoots’. These are the result of heavy pruning where several buds break at roughly the same point on the trunk or branches producing many thin, straight, upright shoots. These can go on to produce flowering and fruiting shoots but only if thinned out to just one or two shoots early in life. Alternatively the whole bunch can be removed if there is already plenty of new shoots on the tree to provide the replacement growth needed.
I hope that the above will encourage you to find a space in your garden for at least one more tree, fruiting or not. October is certainly a good month for planting not only trees but also shrubs, perennials and spring flowering bulbs with the soil still warm and, with the badly needed September rains, now containing sufficient moisture. There are, of course, other jobs to be done in the month and the full list can be found in the blog archives of the Old Railway Line under October 2019 and more detail on what Teresa and I will be concentrating on in our own garden can be found for some reason under September 2020. These include starting to collect fallen leaves to make leaf mould, continuing to work on the lawn, filling any gaps in the beds and borders and cleaning out the greenhouse once the tomatoes have finished cropping. The rest of that blog contained a detailed look at plants which can be relied upon to produce good autumn colour from both leaves and fruit. Also under the same date, September 2020, is a separate blog on some of my favourite shrubs as autumn is such a good time to plant these. In October 2021 the blog concentrated on some of the wonderful plants to be found at Aberglasney in October and having just looked back through this blog and its photographs I am reminded about how good the gardens still look at this time of year. As such they are well worth a visit in person but if you can’t make it then a virtual visit via the blog might prove to be a reasonable alternative. Finally just a reminder that under June 2021 there is a list of all the blogs I had written at that stage which just makes some of the topics covered easier to find in the archives.
I will be back in November with some more gardening thoughts and ideas but until then have a good October, keep well and keep gardening.
Keith.