Head Gardeners’ tips
September 2024

September is a wonderful time to enjoy the rich late-season blooms, the bustling activity of wildlife, and the lingering warmth of summer. As the growing season winds down, take a moment to savour the fruits of your labour and the natural beauty that surrounds you. Here are some tips to guide you through this transitional month.

September offers the perfect opportunity to reflect on your garden. Consider how your plants have performed and if any adjustments are required. For example, ask yourself which plants have thrived, and have any become too dominant? If some plants have struggled, try to determine why and consider whether moving them to a different location might help. Think about whether you’d like to increase diversity or introduce more seasonal colour. For instance, at Horatio’s Garden Wales, this time last year we wanted more colour in some of the beds. We decided to use dill, which is easy to grow from seed. Now it’s thriving and provides a bright splash of yellow amongst rich brown grasses such as Deschampsia.

Once you’ve gathered your ideas and made a rough plan, it’s time to take action. Introducing new plants to the borders is an opportunity to get really creative and there are several approaches you can take:

• Lifting and Dividing Perennials: In early autumn, you can dig up herbaceous perennials that have fibrous roots and divide them into chunks, which you can then grow on. At this time of year, the weather isn’t too hot and hopefully there are enough rain showers to keep your plants well-watered. The soil is still warm as well, which encourages root establishment before winter. Be sure to trim off about a third of the vegetative growth to minimise the chances of your plants wilting and help them settle in. If you divide lots and have more plants than you need, you can pot them up for future use or share them with friends.
• Taking Cuttings: At Horatio’s Garden Wales, we take semi-ripe cuttings of all our tender salvias and pelargoniums. These are really easy to grow, and we store them in the greenhouse over winter to ensure they survive the cold. There will probably be plenty of plants in your garden that you can propagate from cuttings. Give it a try – it’s great fun, and success might come easier than expected.
• Tree Planting: Trees provide long-term benefits, enhancing biodiversity and adding year-round beauty and structure to your garden. Don’t worry if you’re short on space; there are plenty of small varieties to choose from. My personal favourites include Acer, Amelanchier, and Cercis. September is the ideal time of year to plant trees because they’re going dormant and will have plenty of time to establish stronger roots before the following growing season.
• Saving Seeds: There are lots of plants you can collect seeds from at this time of year. For example, nigella, poppies, and cosmos are perfect for saving now. Wait for a dry day and if they’re ripe they’ll probably come away from the plant easily. Store seeds in a cool, dry place until next spring. If you’re eager to keep growing plants, you can start sowing certain seeds now such as sweet peas, calendula, and broad beans. Herbs can also be grown indoors year-round, providing fresh flavours for your kitchen.

September is also about celebrating the harvest and enjoying the fruits of your labour. Continue picking annual vegetables and keep deadheading late bloomers, such as dahlias, to maintain colour in your garden. Don’t forget that one of the greatest joys of having a garden is simply spending time in it. Make sure to pause and appreciate the garden you’ve nurtured. Take in the sights, sounds, and scents around you. Just experiencing the garden can be soothing for the mind, helping to clear your thoughts and recharge your energy. Plus, the gloriously hot sunny days won’t be here much longer, so make the most of them while you can.