September – Charlton and Blackheath Amateur Horticultural Society

Pat’s 10 jobs for September 2026

Pat's Dahlias — Get more *Dahlia* flowers by regular deadheading,
make comfrey tea plant food, and learn from Beth Chatto’s dry garden

Comfrey ready to make comfrey tea — Get more *Dahlia* flowers by regular deadheading,
make comfrey tea plant food, and learn from Beth Chatto’s dry garden

1. Keep cutting or dead heading your Dahlias to keep the flowers coming, hopefully into October. Give them a weekly feed too.

2. It’s not too late to make some comfrey tea to feed your plants and veg. Just cut up handfuls of leaves and leave in a bucket with some water and a weight to hold it down. Try to cover the bucket as the smell is very unpleasant, then dilute 1/10 in water and aim at the base of plants you are trying to keep going.

3. I think this year we need to carry out a review of very dry areas in our gardens and replant with drought tolerant plants. If you made the visit to Beth Chatto her dry garden is an excellent example. I have a bank at the back of my garden and half of it looks very sad or even dead so I’ll be replanting some of it in the spring if things don’t come through.

Beth Chatto’s Plants and Gardens, September 2026

Looking toward the Water Garden. Beth Chatto's, September 2026

Last Friday, a full coach of CABAHS members took another trip to Essex, this time to see Beth Chatto’s Plants and Gardens. The last group visit was in 2021 and the irony of visiting a world-famous dry garden in torrential rain was not lost on those who attended then. A heavy downpour on Friday’s journey made us wonder if we might be reliving the experience, but it was brief and our whole visit was dry.

Most well-known is the Gravel Garden, which was developed in the 1990s on the former car park – at a high point in the gardens which, in Essex, are in one of the driest parts of the country. But the site has a much more varied topography and ecology than just the dry garden. Much of the site was actually boggy and Beth and Andrew Chatto carved ponds in the lowest areas. This meant that we saw green, green lawns in an area – the Water Garden – where the water table, even after this summer drought, is high.

Butomus umbellata and Thalia dealbata in the Water Garden. Beth Chatto's, September 2026 — The Water Garden and surrounding beds

Metasequoia glyptostroboides (dawn redwood). Beth Chatto's, September 2026 — The Water Garden and surrounding beds

Autumn Flower, Fruit & Vegetable Display 2026 – classes to enter

This year’s Autumn Show will be held on Monday 21 September, at 7.30pm in the Old Library at Charlton House.

Here’s a reminder of last year’s show – a groaning table of entries…

The classes you can enter this year are shown below, please have a go at as many as you like!

September 2025 Meeting and Show Table

This month’s meeting included an interesting talk from Clare Lanes about the three-year renovation project of the Rose Garden at Greenwich Park, the monthly Show Table display, the raffle, the potato competition, the sales table and of course plenty of chat and information about upcoming events (NB: Horn Fair on 19 October!).

Plants of the Month: The annuals (September 2025)

If your own space is looking ‘a bit green’ at the moment, think about adding annuals to liven up your garden in 2026. Here are a few I highly recommend:

Zinnia

This year I’ve grown Zinnia elegans SPRITE MIXED at my allotment and they are looking good – tall, healthy, robust, colourful and bee-friendly. I am very pleased with them, as the flowers themselves are a mixture of vibrant and subtle shades, and, as an added bonus, no signs of stem rot (fungi/bacteria more prevalent in warm, wetter summers that attack the stems).

I sowed the seed straight into the soil in two rows. Two or three weeks later, I thinned the seedlings and replanted those thinnings into a third row. So, they are tightly packed and they don’t seem to mind that and I don’t need to stake them. Flowering from July to October, this robust variety is perfect for displaying in gaps in borders or containers. And ideal for picking, although I don’t have the heart to do that yet!

Compton Acres, Poole, Dorset

Before the 1920’s, the ten acres of land at Canford Cliffs was heathland. But along came a man with vision, one Thomas William Simpson, and, with the help of his head gardener Mr Middleton, a magical garden was created.

Mr Simpson was a businessman and entrepreneur (margarine) and having visited many countries, knew exactly what he wanted. Influenced by the gardens and architecture of Italy, Japan and the UK Arts and Crafts movement, he and his gardener set about creating a series of gardens, starting with the Italianate gardens, then a necklace of paths and ponds which connected finally to his Japanese Garden, thus turning his vision into reality, right up until WW2.

The garden sadly fell into neglect following the conflict, but in the 1950’s and 60’s, a new owner set about restoring it, planting the magnificent trees we see today – their maturity and majesty makes this garden quite a magical place to explore.

The steps leading down to the Italianate Garden — The Italianate Garden

Upon entry into the garden, I came into the Roman Garden, passed through the Grotto and into the very impressive Grand Italianate Garden, the focal point being the rectangular formal pond and beyond, the statue of Bacchus, the Roman God of Wine, sheltering within a temple at the far end of the garden. This sheltered, south-facing, formal garden is a relaxing place to sit and admire its many features. This garden then leads into Palm Court, a formal garden with its row of impressive Chusan palms.

Moth Night at the Old Pond Garden 18/19th September 2024

Jason Sylvan, Head Gardener at Charlton House, has designed the Old Pond Garden to be as attractive to wildlife as possible. Because we talk about monitoring moths, he asked if we could check how many moths are visiting the garden. We should have tried this in the warmer months when there are more plants in full flower but we had missed that for this year so we gave it a shot on a warmer dry night in September to test out a strategy.

As we wrote in an earlier post, we have been monitoring moths for the Garden Moth Scheme since 2013 in Newcastle-upon-Tyne and since 2019 in Blackheath. The moth trap is a box with a light (our type gives off no heat), and below the light are two panels of see-through Perspex, one each side and shallowly angled down, with a slot/gap between them. The moths ‘funnel’ into the box, and it’s difficult (but not impossible) to get out. Inside are egg-trays, which provide resting places.

Why do moths fly towards the light? Until recently, the correct answer has been that nobody knows, but researchers in Sweden found the answer: for aeons, light at night was above and dark was below, so moths orientated themselves to fly with their backs to the light above. In artificial light – fires, candles, street lamps – they still try to fly with their backs to the light, circling round and round, and sometimes become disorientated.

The trap is placed before sunset, and collected at sunrise the next day. So an early start.

Autumn Flower, Fruit and Vegetable Show 2024

The 2024 Autumn Show was held on Monday 16th September in the Old Library of Charlton House. It was well attended and the standard of entry was very high – particularly given the strange growing year we’ve had.

Whole table of entries and audience awaiting decisions

Jason judged the flower classes and Melanie the vegetables but there was lots of discussion between the judges and Stella, the Chair. Anna judged the cakes and preserves, ably assisted by Annette, and Hugh weighed the potatoes. As ‘Best in Class’ winners and ‘Highly Commended’ entries were announced, the judges explained the reasons for their decisions. Finally, they agreed their choice for Best in Show.

Plant of the Month: Clematis (September 2024)

What a struggle it has been to protect the shoots of these two clematis from sustained attacks by the usual culprits this year! Not only did I use a garlic spray (one clove of garlic simmered in water) but I also liberally (and continually) sprinkled spent coffee grounds around the base of the plants. Although they were saved, I did lose other clematis: scented C ‘Betty Corning’, C ‘Rising Star’ and C ‘Wedding Day’ – all absolutely lovely and such a loss that I will need to repurchase them.

Clematis ‘Princess Diana’
This clematis is definitely one of my ‘top five’. The tulip-shaped flower is an unusual shade of bright pink, with beautifully striped markings both inside and outside of the petals (sepals). This variety (texensis) was introduced by a British breeder to honour the Princess of Wales in 1984 and has deservedly been given the RHS Award of Garden Merit.

Clematis 'Princess Diana' showing beautiful markings — Clematis ‘Princess Diana’ showing beautiful markings

Clematis 'Princess Diana' mid-September 2024 — Clematis ‘Princess Diana’ showing beautiful markings

As to be expected ‘Princess Diana’ came into flower late – in July, rather than June – and has been flowering continually, with eight flowers and a few buds on the vine at present.

Pat’s Jobs for September 2024

1. Start ordering your bulbs now as all the bulb catalogues are arriving – though prices don’t stop going up!

2. Start planting bulbs when they arrive but save your tulips until later as they are prone to virus and rotting, and to theft by squirrels.

3. Divide large established clumps of perennials by cutting back first, then splitting either by hand or with two forks back to back. Delay if soil is heavy or too wet.

Split established clumps of perennials — Order Spring Bulbs

4. Replace tired summer bedding in pots and replant for winter and replenish with fresh compost.