As we speak, apples and pears are ripening on the trees. But how do you grow apple and pear trees from scratch and keep them alive? Our resident gardening expert, Professor Geoff Dixon, investigates.

Autumn is the ‘season of mists and mellow fruitfulness’, as John Keats said in his Ode to Autumn. It is a time for harvesting temperate tree fruits, especially apples and pears in gardens and orchards.

This fruit is distinctive and delicious. The ‘Sunset’ apple cultivar, derived from the Cox’s Orange Pippin, produces red and gold striped fruit and sweet tasting flesh, while the French pear cultivar doyenne du comice has the most superb taste if caught at peak ripeness.

The sunset apple.

Both apples and pears ripen after harvesting, emitting ethylene and passing through a climacteric, or critical biological stage. When respiration reaches a peak, the fruits’ flavour is most satisfying.

Both apples and pears are best planted in late autumn or during winter when the trees are dormant, either as container-grown or preferably bare root trees. Place each tree in a hole that is large enough for the entire root system, ensuring that the graft union sits well above the soil level.

Each tree consists of two parts: the rootstock, selected originally from wild species, and the scion, which is the fruiting cultivar. Apple cultivars mostly dwarf Malling no. 9, and pear scions are grafted onto quince rootstocks. A stake should be driven into the hole before putting the tree in place.

Pour ample water into the hole, keeping the roots wet. Do so again once soil is replaced and firmed round the tree. As the tree establishes and produces leaves and flowers, water well and regularly, especially during dry periods.

French pear cultivar doyenne du comice

Feed with fertilisers that contain large amounts of potash and phosphate but minimal nitrogen. This encourages vigorous root growth. Sprinkling compost or farmyard manure around the tree helps retain soil moisture.

Climate change is having significant deleterious impacts on all members of the Rosaceae family, including apples and pears. Australian studies indicate that temperatures are reaching higher than the evolutionary maximum for these species.

This stresses the plants. It adversely affects their health and performance and reduces their ability to store carbon and produce fruit crops.

The pear scab Venturia pirina

Levels of pest and disease infections are increasing. In particular, sap-sucking woolly aphids (Eriosoma lanigerum) have increased from minor to major apple pests in the last decade. Pear scab Venturia pirina has become a major cause of defoliation.

Chemical control options for both are limited, but regular drenching sprays with seaweed extracts may reduce their impact. Seaweed extracts additionally provide some foliar absorbed nutrients and increase the visual quality of fruit.

Professor Geoff Dixon is author of Garden practices and their science, published by Routledge 2019.

Which species can you plant to increase the nutrients in your soil and boost biodiversity, and which pathogen tackles some of those pesky weeds? Our resident gardening expert, Professor Geoff Dixon, tells us more.

The term ‘sustainability’ for gardening means replacing what you take out of the soil and supporting localised biodiversity. Harvested crops, for example, take out nutrients and water from the soil. Replacements should be supplied that aid biodiversity and have minimal impact, or zero impact, on climate change.

Seaweed (Ascophyllum) has been recognised as a valuable fertiliser source in British coastal areas for centuries. Now, proprietary seaweed extracts are gaining popularity either when applied directly as liquid feeds or sprays, or when added into composts.

Classed as biostimulants, seaweed extracts contain several micro-nutrients and a range of valuable plant stimulatory growth regulators. They encourage pest and disease tolerance, increase frost tolerance, stimulate germination, increase robust growth, and add polish to fruit such as apples and pears.

Seaweed bolsters some of the nutrients lost through gardening. Image from Geoff Dixon.

Benefits of borage

Some plants are very effective supporters of biodiversity. Borage (Borago officinalis), known also as starflower or bugloss, is a robust annual plant of Mediterranean origin with pollinator-attractive blue flowers.

It is very drought resistant and suitable for dry gardens. Although an annual, it is self-seeding and could spread widely. It is very attractive to bees as it produces copious light – and delicately flavoured honey.

Its flowers and foliage are edible with a cucumber-like flavour, making it suitable in salads and as garnishes, while in Germany it is served as grűne soße (green sauce). When used as a companion plant for crops such as legumes or brassicas, it will also help to suppress weeds.

Borage is good for bee and belly. Image from Geoff Dixon.

Weeding out the problem

Weeds are a continuous problem for gardeners and their prevalence varies with the seasons. Groundsel (Senecio vulgaris), also known as ‘old man in the spring’, persists whatever the weather.

It is ephemeral but can seed and regrow several times per year. As a result, once established, it is difficult to control without very diligent hand weeding and hoeing out young seedlings before the flowers form.

There is, however, a form of biological control that can aid the gardener. Groundsel is susceptible to the fungal rust pathogen (Puccinia lagenophorae). This pathogen arrived in Great Britain from Australia in the early 1960s. Since then, it has become well established and outbreaks on groundsel start to become obvious in mid- to late-summer, especially in warm dry periods.

A fungal pathogen can kill groundsel, a weed that comes through several times a year. Image from Geoff Dixon.

Severe infections weaken, and eventually kill, groundsel plants. Gardeners should take advantage of the infection and remove the diseased weeds before any seeds are produced.

>> How else has climate change changed the way our gardens grow, and what can be done to alleviate its effects? Geoff Dixon investigates.

Professor Geoff Dixon is author of Garden practices and their science, published by Routledge 2019.

Written by Professor Geoff Dixon. You can find more of his work here.