Ann Treneman’s guide to sustainable container gardening

One of my favourite days at an RHS Chelsea Flower Show was in 2022 when my friend, Ann Treneman, had a sustainable container garden on display and asked me to help her hand out leaflets and generally chat to people about it.

The Sustainable guide to Growing Flowers, Shrubs and Crops in Pots
Ann Treneman and the RHS

Ann and I are working together on a project to restore a rare 18^th century town garden at Bromley House Library in Nottingham, so I’d have been gutted had she not asked. The cheapskate in me was glad of the free ticket, too!

It was enormous fun and I was thrilled when Ann’s “Wild Kitchen Garden” (a garden of pots, each planted with edible plants of various sorts) won a “People’s Choice Award” and a silver gilt.

Now she has produced a book for the RHS – “The Sustainable guide to Growing Flowers, Shrubs and Crops in Pots”.

Martin and Ann at RHS Chelsea 2022 (left) and Ann Treneman’s RHS Chelsea Garden (right)

Anne’s almost apologetic about the book’s title. “’Sustainability’ is a failure of a word to me. The moment you say it people either start to fall asleep or get riled up. It feels tiresome – like there’s a bossy boots person there who’s going to punish you if you don’t have exactly the right kind of dahlia or something like that.

“People think sustainability is all or nothing. They’ve got to learn to love slugs and their lawn needs to be a prairie. Or at least full of weeds. They think you’ve got to have a bison in your back garden or you’re just not really trying.

“My own gardening habits were well meaning but extremely haphazard, I was peat-free – most of the time. I killed slugs. But I was obsessive in trying to help the ladybug. I often didn’t grow plants from seed even when it was entirely possible.

“Becoming a sustainable, greener gardener is all about changing habits. The catalyst for me was being chosen to do the container garden at Chelsea. The RHS really doesn’t give you any choice – you are going to be sustainable. That’s it. And it was really helpful to have someone just lay the law down to me like that.

“What I found was that it’s actually quite fun to be a greener gardener. It encourages you to do some interesting, bold things. I’ve discovered that it doesn’t have to be difficult either. And it’s not all or nothing. You can have your little secret, tidy lawn and you don’t have to be a goody-two-shoes, or even smug – although it is quite fun being a little bit smug.”

As you can imagine, then, this book is encouraging. It makes you realise sustainable container gardening need not be too difficult.

I’ve owned and ignored plenty of container planting books over the years. Most ended up at Oxfam. So what about this one?

Watering toil

I have a couple of issues with pots. Watering them. I hate the job. I’m happy walking round the garden deadheading roses and pulling off damaged leaves, but watering feels tedious. It also has to be done or the plants die. In contrast, if you leave deadheading for a week, it’s not the end of the world. So, for me, watering is a chore, not an act of mindfulness.

I’m all for not using peat – and have been peat-free for several years. But I find many modern soil mixes don’t help my watering aversion. They don’t hold the water as effectively as peat-based mixes. The water seems to run straight through and out of the bottom of the pot!

So fed up was I that this spring I moved all my roses out of pots and planted them in beds. I think once their roots are established roses in the ground cope remarkably well with dry spells and better than if they are relying on me to water and feed them every couple of days. Having emptied a lot of pots I had no plans to refill them. But Ann has encouraged me to give the sustainable container garden another go.

Sustainable container garden

Ann Treneman giving a workshop on sustainable container gardening at Bromley House Library

The book advises on clustering pots for effect. So instead of having them spread around the garden I’ve moved most to one spot and tried to create something that looks more artistic.

Ann says: “The classic design concept for a pot arrangement is to have a ‘thriller’ – something that makes people go ‘wow!’. Then a ‘spiller’ – something that cascades over the pot. And, finally, a ‘filler’ – like a mid-height salvia.” I’m looking forward to trying that.

The other advantage of clustering is that it makes watering the pots easier – helpful for any friends when I’m on holiday, too. I’m going to put saucers underneath to collect water and, next year, will experiment with a self-watering (wicking) bed.

Ann warns against watering every day unless the soil is dry right through. It is more effective to water less often but really make sure all the soil gets a good soaking.

Encouraged by the book, I’m also going to experiment with making my own potting medium, using compost from the hot bin, perhaps some soil and horticultural grit or sand.

And I’m going to sort the water butt. I’ve needed to get one or two for a while. I think part of the reason I hate watering is not just the tedium of the job but the guilt that goes with it.

I’m a sucker for going to garden centres and buying plants to fill temporary gaps in the beds. Now I’m going to use my pot corner to sow annual seeds of things like Rudbekia and cosmos. They may stay in their pots, or I might try to plant them on. And I’m going to grow more herbs. All from seed. This should reduce my use of plastic, stop the garage filling up with empty plant pots, and save me a fortune at the garden centre and supermarket.

I like the idea of a pond in a pot. I think that could be fun.

This little book (175 pages) meets the needs of beginners, and intermediate gardeners like me. It’s something I will return to for advice ­– particularly the lists of plants to grow towards the end.

And, of course, anyone who’s enjoyed Ann’s weekly columns in the Times for years, knows she’s a great writer, so it’s incredibly clear. It’s also well designed. Yup, a book on container planting that isn’t going to Oxfam.

Martin paid for his own copy of the book. In so far as it can be, this review is impartial.