Pruning certain plants now will ensure they are covered and healthy over winter, but also ensure there is strong growth and plenty of flowers in the following year
Angela Patrone Senior Lifestyle Reporter and Isobel Pankhurst Audience Writer
12:16, 23 Sep 2025
Monty Don shares 3 plants to prune in September so they will be ‘packed with flowers’(Image: Dougal Waters via Getty Images)
Trimming plants can have a substantial effect on their development in the coming year. Cutting back is crucial for maintaining plant health, vitality, and equilibrium, as well as stopping larger varieties from dominating the garden.
Monty Don, in his most recent gardening blog post, has named the essential plants that need trimming in September, alongside other crucial gardening jobs for the month. Before starting to prune the plants Monty suggests, gardeners must make sure their secateurs are clean and razor-sharp.
Dull or faulty blades can create jagged cuts, potentially damaging the plant and raising the chance of disease.
Plants to prune in September1. Lavender
Lavender must be “pruned every year” to “avoid woody, leggy plants”(Image: Ekaterina savyolova via Getty Images)
According to the gardening expert, lavender must be pruned every year to avoid “woody, leggy plants”. He suggested not waiting until seed heads develop or flowers turn brown, as early trimming allows maximum regrowth time before winter.
Cut back boldly to create a neat shape, but retain some new shoots on each stem, as lavender may struggle to regenerate from bare wood.
These fresh shoots will “grow fast and provide an attractive and healthy cover”, protecting the plant through winter and establishing the foundation for next year’s blooms.
2. Shrub roses
For summer-fruiting raspberries, it’s time to cut down the old brown canes to ground level(Image: popovariel via Getty Images)
Shrub roses are celebrated for their hardiness and abundance of flowers from summer through to autumn. By trimming your roses, you’re setting the stage for more robust growth and an enhanced flowering period next year.
For those who might feel nervous about pruning roses, there’s no cause for concern, especially with varieties such as gallicas, English roses, albas, or hybrid perpetuals. Monty advised that these types are “best simply trimmed with shears any time this month,” making them ideal for a more natural garden environment, such as a wild garden or a less structured cottage garden.
The gardening expert recommended: “Do not worry about the position or angle of the cuts, but clip away all long and straggly shoots as though you were trimming a hedge. Leave a compact, slightly domed bush that is about two-thirds of its former size.”
He added: “In March, when you can see clearly without any foliage, you can inspect the shrub to remove any damaged or rubbing stems, but a simple shear in September is enough to keep it healthy and packed with flowers next year.”
3. Raspberries
For summer-fruiting raspberries, it’s time to slice down the old brown canes to ground level, keeping the fresh new green canes untouched. The 70-year-old specialist observes that these new canes will yield next summer’s fruit and preserve the plant’s “healthiness”.
Gardeners are encouraged to reduce these down to the six strongest shoots, removing all weaker or awkwardly placed growth. The surviving canes will require secure support for the following year; therefore, summer raspberries are “best grown” against a permanent support framework.
Monty explained that he secures the canes with twine to parallel wires firmly attached between robust posts, weaving around them and distributing them evenly as he progresses along the wire at each level. He added: “It is important that it is really secure as winter winds can catch and damage them.”
When left unmanaged, these plants can become congested, leading to diminished fruits and an invasion of their designated area. Furthermore, the stems that have produced fruit will start to weaken over time and ultimately perish.
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