One of the great benefits of being a horticulturist is the connection with the natural world, and this is true of anyone who spends time outside observing their surroundings, whether it be the plants in our gardens or in the wider landscape, migratory birds, or even the cycle of the moon.
During my horticultural career I’ve observed the inevitable seasonal shifts of flowering and fruiting, but also daylight hours, weather, and even the first mowing of the lawns in spring. These observations can help with planning and maintaining a garden, no matter what size, but on a personal level also help anchor me and provide a sense of calm.
For me there is something humbling about the changes in the seasons, the weather and the gardening calendar. During the darkest and coldest winter days, there’s always an optimism that days will lengthen, the light brighten and temperatures rise, and with that comes the bursting of buds and spring blossom. In contrast there is a point in autumn where the shortening days, cooling temperatures and turning of leaves indicate a time to tidy the garden, clear away the old and make way for the new. Even those of us with limited access to the great outdoors are influenced by the seasonal rhythms of the natural world.
Nature's calendar
In a garden, being in tune with seasonal shifts, or nature’s calendar, can influence what we grow, and how we grow it, but we needn’t limit observations to the seasons. Noticing a change in temperature and rainfall from one week to another can affect how we grow our plants and maintain our gardens. Low spring temperatures can impact sowing times for crops, while extended periods of drought influence not only watering regimes, but also decisions about what we might grow in the future.
On a large scale, watching the turning wheel of nature can inform horticultural practices, and on a personal level, observing nature in our own gardens can be equally useful. Today, in a changing climate, observing nature’s calendar is more relevant than it has ever been. In the past, seasonal changes in temperature, rainfall and day length have been generally predictable, but even small variations in climate can result in a shift in timing of ecological patterns, wildlife behaviour and ecosystems. The succession of heatwaves during summer this year, combined with a prolonged drought, has affected not only human behaviour, but also our gardens, wildlife, landscapes, ecosystems and farming.
UK records show that oak trees now come into leaf one month earlier than they did in the 1950s, while snowdrops appear two months earlier than they did in the 1950s. For us as gardeners, this may mean a change in the appearance of our gardens, but for wildlife such changes may be dramatic. Pollinators reliant on certain species for nectar may now have no food source, while insects reliant on oak trees for food or shelter may also struggle. In turn, the impact on food production may also be detrimental, with a fall in pollinators and periods of drought severely affecting crop yields.
Since 2022, we have been carrying out a Phenology Project at Cambridge University Botanic Garden in which we record leaf, flower and fruit development, along with leaf colouring and leaf fall in 90 tree species. Since the Project started, we have noticed that there are definite shifts in the timing of these occurrences. As our data set increases, we will be able to build a picture to help us understand the effects of climate change, and also to help us grow and conserve plants in the future.
Climate change impacts on gardens
As autumn creeps towards us we can expect to see leaf colour, leaf fall, hedges full of hawthorns and sloes, and the onset of the first seasonal frost. But this year, given extreme summer weather, autumn may not be as predictable as it once was, potentially resulting in less autumn colour, early leaf fall, fewer fruits in our hedgerows, and fewer or less severe frost than we may have experienced in the past.
The impacts of any shifts in our seasons and weather may not be entirely predictable, but by observing seasonal biological changes in our own gardens, as gardeners we are all probably noticing changes in flowering time, or in the occurrence of frosts. In noticing these changes many of us are already adapting our own gardening practices to suit a changing climate. While we may not be aware of it, gardeners are very much in tune with nature and shifts in nature’s calendar.
Gardening jobs for October
- Plant trees and shrubs and hardy perennials once the soil is wet but ensure you keep them moist over winter.
- Sow seed of perennial plants such as Astrantia, Achillea and Centranthus.
- Sow green manure to protect soil over winter and sow hardy crops such as broad beans and peas for harvesting in late spring.
- Clean your greenhouse and cold frame ready for overwintering tender perennials.
- Collect fallen leaves from the garden and add them to your compost bin or make a leaf litter bin for mulching the garden when the leaves have rotted down.
- Spike compacted lawns and backfill the holes with fine grit or sand to improve drainage.
