What to Plant in Your Garden This September
September is such a beautiful month in the garden here in South Wales. The light softens, the air feels fresher, and while summer flowers begin to fade, there’s still plenty of colour and life around.
In Spring we anticipate the acceleration of growth and new beginnings, but Autumn is all about anticipation too. I am anticipating the first day I wear a jumper in the garden, the sound of autumnal rain but more importantly cosy evenings with Russ and our two cats, while enjoying beautiful food seasoned with foodie herb plants.
It’s also a brilliant time to get planting. The soil is warm, the weather is cooler, and plants have a good chance to establish roots before winter.
Here’s what I recommend planting this month if you live in Mid Glamorgan (or anywhere nearby):
🌱 Herbs for the Kitchen
September is the perfect moment to freshen up your herb garden. Hardy herbs like rosemary, sage, thyme, and chives will settle in nicely now and be ready to thrive next spring. Local wildlife will love the bright red flowers of Creeping Red Thyme but you will also love the evergreen foliage that provides interest in your garden throughout the year. Parsley and coriander can also be sown in pots or borders — they don’t mind the cooler weather.
🧄 Veg for the Kitchen Garden
If you’ve got a vegetable patch or kitchen garden, there’s still plenty you can do this month:
Garlic & onions – Pop them in now for a lovely crop next summer.
Spinach & winter lettuces – These will give you fresh leaves in the cooler months.
Broad beans – They can be sown in September and will reward you with an early harvest next year.
I always find it so satisfying to keep my kitchen garden and greenhouse productive well into winter.
🌸 Perennials & Shrubs for Borders
Autumn is one of the very best times to plant hardy perennials and shrubs in your borders. Plants have the chance to develop strong roots over winter and really get going in spring. A few of my favourites to plant in September are:
Asters (they look stunning now and will keep flowering into autumn)
Rudbeckias
Hardy geraniums
Shrubs like viburnum or hydrangea
🌿 Splitting & Replanting Perennials
If you’ve got big clumps of herbaceous perennials, September is the time to lift and divide them. Not only does this refresh the plant, but you also get extra clumps to plant in other parts of your garden. Hostas, daylilies, and irises all respond really well to this.
🌸 Collect & sow seed from hardy annual & perennials
This is a great opportunity to increase the number of plants in your garden for free.
Growing plants from seed is generally straightforward and inexpensive. Harvesting seeds and berries can be fun but it does take a little understanding and planning.
A Final Tip: Mulching
Once planted, it’s well worth adding a good layer of mulch around your borders, shrubs, and herbs. It keeps weeds down, protects roots, and improves soil health over the winter.
Need a Hand?
I know autumn gardening can feel like a long list of jobs, but September really is one of the most rewarding months to get outside. If you’d like a hand with planting, splitting perennials, mulching, or setting up your kitchen garden for the colder months, I’d love to help.
I work across the Mid Glamorgan area, looking after borders, shrubs, herbs, and greenhouses. Just get in touch and I can help you get your garden looking its best for the months ahead.
Happy planting,
Holly x
