Heaven scent

AUTUMN is my favourite time of the year at RHS Garden Harlow Carr. The garden is ablaze with stunning autumn colour, from fiery reds to rustic bronze and vibrant hues of amber and gold. I particularly enjoy the sound of leaves being crushed under foot and the beautiful burnt sugar scent of the Cercidiphyllum japonicum tree – commonly known as the Katsura tree – with its heart-shaped leaves which turn yellow, orange and pink in autumn.

The surprising smells of autumn turn my mind to summer scents and importantly, the preparation that needs to be done now to ensure the garden is as fragrant as it is beautiful. A popular choice for summer scent is of course, the sweet pea. If you have not already done so, you can start to sow your sweet peas now and right the way through to the end of November, or even as late as February. This will ensure you get the best from your seeds, getting stronger and earlier flowering plants. If you keep on top of deadheading, this will also extend the flowering season.

Choosing your sweet peas can be a tricky task as there are so many varieties available: there are sweet peas for exhibition or decoration; some with long stems; others with short; highly scented varieties, old-fashioned or mixed sweet peas. Specialist seed catalogues are a useful tool to help pick the right variety for you. Try those from the Sweet Pea Society, Kings Seeds, Nicky’s-Nursery, or Thompson and Morgan.

Start the seeds off in a warm greenhouse or your window sill in deep-bottom pots or, as we do at Harlow Carr, in root trainers. Growing in pots helps them develop a good root system when ready for planting in April. Sow six to seven seeds to a 13cm pot, spacing the seeds a couple of centimetres apart.

Once the seeds have germinated, remove from the heat to avoid the plants becoming leggy. You can encourage your sweet peas to become as strong as possible by exposing them to colder temperatures. Place them in a cold frame if you have one or simply somewhere cool in your house. You may need to protect the plants if night time frosts are forecast. Pinching out can be done if sown in autumn once the plants reach about 10cm to encourage branching.

April is the time to plant. Check both the weather forecast and soil temperature before doing so. Sweet peas prefer to be grown in a well-cultivated soil with well-rotted manure which should be added to the soil in autumn or early winter. Alternatively, you can sow directly into the ground in April but this results in weaker plants and fewer flowers.

If you have poor soil, your plants will benefit from being fed with a general fertilizer every couple of weeks. A potash-rich tomato feed works well to keep them flowering. Remember to keep deadheading otherwise they will produce more seeds and no flowers. Why not come to RHS Garden Harlow Carr to get some expert advice for your garden?

Jobs to do

Start planting your bare-root fruit trees and cane fruits in the ground

Continue to pick your winter greens to ensure a constant supply of new growth

Move tender crops such as citrus plants into a heated greenhouse

Take out any dying plants to stop the risk of pests and diseases in the garden.

With thanks to Joe Lofthouse, horticulturist at RHS Garden Harlow Carr

For more information on things to do in the garden this month visit rhs.org.uk

Diary dates

November 10 to 29: Art & Craft for Christmas Exhibition

This exhibition is an opportunity to buy bespoke and handmade Christmas presents, with plenty of beautiful items on sale. Normal garden admission.

December 4 to 6, 11 to 13 and 18 to 24: The Magic of Christmas

Decorate a gingerbread man, write and post a letter to the North Pole, explore the garden on a Christmas trail and add your wish to our festive Wishing Tree. Normal garden admission

December 11: Guided Walk – Harlow Carr at Christmas

Join Harlow Carr’s garden manager, Katherine Musgrove, and discover the special plants that provide winter beauty in the Winter Walk, woodland and ornamental borders. Booking is essential and fees apply. Call 020-3176-5830.