The garden is starting to become bare, the leaves are accumulating on the ground and those now dry branches seem to just ask for a good pruning. With the arrival of November, the temptation to put everything in order before winter is strong. Yet, right now, a pruning done at the wrong time could cost us months of blooms.
The reason is simple: not all plants follow the same calendar. Some shrubs have already formed, between summer and autumn, the buds that will open the following year. Cutting the branches therefore also means eliminating future flowers. For other species, however, the stems that now seem useless represent a natural protection against lower temperatures.
As the experts of the Royal Horticultural Society (RHS), one of the main British institutions dedicated to gardening, also remind us, knowing when not to prune is as important as knowing pruning techniques.
So let’s see four common plants in our gardens on which it is better not to intervene in November, with an important clarification: the right time to prune also depends on the variety and the climate of the area in which we live.
Hydrangeas: Those dried flowers still have a function
Hydrangeas are among the most loved ornamental plants, thanks to their large inflorescences which can go from pink to blue, from white to purple. When autumn arrives, however, the flowers lose color and dry out, giving the impression that the time has come to cut them.
It’s not always a good idea. the globose inflorescence hydrangeas and the umbrella ones, belonging above all to the species Hydrangea macrophyllagenerally flower on branches developed during the previous year. This means that the buds destined for the next flowering may already be present on the plant in November.
Vigorous pruning in autumn therefore risks eliminating them, significantly reducing the number of flowers during the following summer.
There’s also another reason to wait: wilted inflorescences can help protect the buds underneath from frost.
When to prune them? Better to wait until spring, when the risk of intense cold decreases. At that point you can eliminate the old flowers by cutting just above a pair of healthy buds and removing any damaged branches.
Be careful, however, not to make all hydrangeas a single category: Hydrangea paniculata And Hydrangea arborescensfor example, flower on new shoots and follow different pruning rules.
Lilacs: the fragrant flowers of spring are prepared months in advance
The lilac (Syringa vulgaris) is one of the shrubs that announce the arrival of the summer with clusters of highly scented flowers, generally in shades of purple, lilac and white.
Its spring flowering, however, does not arise out of nowhere. The flower buds develop during the previous season and remain on the branches throughout the winter, waiting for favorable conditions to open.
If we decide to shorten the lilac in November to make it tidier, we could unknowingly eliminate the very branches that would have produced the flowers.
The best time to prune it is immediately after flowering, generally between May and June, based on the climate and variety. This is the time to eliminate withered inflorescences and, when necessary, prune out older or too thick branches.
In autumn, however, it is best to leave it alone. Even though it has lost its leaves, it is already retaining some of its spring show.
Forsythia: do not cut branches now that will turn yellow
Forsythia (Forsythia) is one of those plants that manage to transform the garden when everything else still seems asleep. Between the end of winter and the beginning of spring, its branches are covered with small, intense yellow flowers, often before the leaves even appear.
The secret of this early flowering is precisely in the branches of the previous year, on which the buds have already formed.
Autumn pruning, especially if abundant, risks compromising the spectacular effect that makes this shrub so appreciated.
It is therefore better to wait until the forsythia has finished flowering, generally between March and April. Immediately afterwards, the branches that produced the flowers can be shortened and some of the older ones can be eliminated, encouraging the growth of new shoots.
There is also an advantage in not intervening too much: left to grow naturally, forsythia maintains an arched shape, decidedly more interesting than that of a bush continuously cut into rigid shapes.
A drastic pruning in winter can be useful for rejuvenating very neglected specimens, but the loss of subsequent flowering must be taken into account.
Penstemon: old stems protect the plant from frost
Penstemon is an ornamental perennial highly prized for its tubular flowers, often pink, red, purple or white, which attract bees and other pollinating insects.
Compared to previous shrubs, the reason why it should not be pruned in November is different. It’s not so much a question of preserving the buds of the next flowering, but of protecting the plant from the cold.
Some varieties, especially the less rustic ones, can suffer from winter frosts. The stems left over from the previous season help to repair the basal part of the plant and the new, more delicate shoots.
Cutting them too early means exposing the vegetation more to frost.
It is therefore better to leave the stems during the winter and intervene in the spring, when the temperatures have stabilized. In colder areas it may be appropriate to wait until April or May.
Even a mulch with mature organic material, distributed around the base without suffocating the collar, can help protect the root system.
And ornamental grasses? Better to leave them until spring
There is another category of plants that deserves attention: ornamental grasses, such as Miscanthus, Pennisetum And Calamagrostis.
In autumn their leaves turn yellow, the stems dry out and the ears lose their original color. But what at first glance seems like material to be eliminated still has its usefulness.
The dry parts, in fact, can offer shelter to small animals and insects during the colder months. Additionally, the inflorescences left on the plant also add structure and movement to a winter garden.
For many deciduous grasses, the best time to cut dry growth is late winter or early spring, before new shoots begin to develop.
Evergreen grasses, on the other hand, generally require lighter interventions, limited to the removal of dead parts.
What can we do in the garden in November, instead of pruning?
Giving up scissors doesn’t mean abandoning the garden. November is a great time to take care of the soil and prepare the plants for the winter.
We can distribute a mulch of healthy leaves, mature compost or other organic materials around the most sensitive plants, check that the pots have good drainage and eliminate any broken branches that represent a danger. It is also useful to prevent the soil from remaining constantly soaked in water, a condition which during the cold season can favor root rot.
And above all, we can learn to look at the garden with different eyes: a bare branch is not necessarily a useless branch, just as a dry flower is not always something to be eliminated.
