Spring is officially here and so is the sunshine. And as the buds and shoots start to appear gardening is well and truly back on the agenda. Our resident gardening expert is here to talk us through the pleasure and pitfalls of pots.

Gardening with pots

People often think that it’s an easy option to grow plants in pots but I think it’s really difficult.  That is, it’s difficult to grow healthy, decorative plants – it’s very easy to grow scraggy, half-dead plants!

This is primarily because pots limit the plant’s access to a living soil and nutrients as well as water.  Unless plants are frequently watered, fed and potted-on into fresh soil, they become stressed. Stressed plants are more susceptible to pests and diseases.  Additional problems can arise because pests can proliferate in the confined growing medium – vine weevil being a prime culprit. The larvae have a lovely time munching away at roots in a lovely protected location until the plants collapse.  Watering is a particular problem – even large pots may need to be watered once a day in summer and small pots more frequently – so you either need an (ugly) automatic watering system or very good neighbours if you ever want to go on holiday.

Bad reasons for growing in pots

• Not finding the right place in the garden for an impulsive purchase.
• Deliberate neglect and slow death of a gifted plant that you don’t want!

Good reasons for growing in pots

• Having only a paved yard with no access to soil.
• Having tender plants that need to be moved into winter shelter.
• Framing a hard-surfaced entrance, terrace or pathway. 

Trees and Shrubs: are the most difficult to keep happy in pots – even toughies like olives and bays look sad after a couple of years unless re-potted.  Long-term residents in pots should be given a largely loam based soil – not compost-rich because this will break down quickly and the plant will sink in the pot. John Innes No 3 is ideal.  Ideally, you should repot every 2-3 years – taking the shrub out, washing the soil off the roots and repotting in fresh soil and, preferably, into a larger pot.

Unexpectedly, I’ve found that Camellias are the easiest long-term residents.  I’ve had some (just about happy) in very large pots for over a decade.    One of the problems with large shrubs is that re-potting is physically difficult and topping up the compost has to be done taking care not to cover the stem/root junction.  A handful of blood, fish and bone feed about three times a year and a top dressing of seaweed helps.

Palms, Bay and Olive trees are good pot subjects – drought and starvation tolerant – up to a point – but always happier in the ground. I have two bays that are desperate for an upgrade  – they are showing all the signs of pot misery – small, paler leaves and suckering at the base. I have been looking for pots large enough at a not too exorbitant price. When I find them, I’ll use an old bread knife to saw them out of their pots, wash off the soil and trim back the old roots and the suckers before repotting.

Japanese Acers and Magnolia stellata look fantastic in large pots in a courtyard but are very hard to keep healthy. The Acers, in particular, need shade and plentiful water – a few days of neglect in summer will leave them looking wretched.

Growing in a pot can be used to create a fairly permanent feature – for example to frame an entrance.  If possible, give the tree/shrub access to the ground by making the hole in the base of the pot much larger – this solves all the potting-on, top-dressing and watering issues. You can do this in ceramic pots by drilling a circle of holes and knocking out a larger hole. Basically the pot is not a pot then – just a raised structure to give the plant more presence.

Mini flower beds

Sarah Raven is the doyenne of mixed annual and perennial plantings in pots.  She has a great eye for a good plant but her real genius is in putting them together in lovely colour combinations and voluptuous excess. If you are a committed pot grower, I recommend her book ‘A Year Full of Pots’.  She is a great fan of spring displays of bulbs in pots – layering up different species to flower in succession.  I think this is just too much work – you really need fresh bulbs each year to ensure a good show – what do you do with the old ones? Plant them out or chuck them out? One is hard work, the other is just horribly wasteful.

I find using a single colour makes it easier to get right – like this one at Hidcote Garden

Clusters of pots can be used to create a rotating display, akin to a flower bed.  It can look wonderful but is dependant on having a place for the ex-exhibition plants to hide their shame while they’re off peak. 

Tender plants

I’m a sucker for succulents and I’m not alone – they’ve gained a huge following in recent years.  Most garden centres now offer a few and specialist nurseries like the one at Tremenheere Sculpture Garden are full of temptation.  Those of you on the coast may be able to keep near-hardy succulents outside all year, we inlanders lose them to wet feet and the odd frost if they are in the ground. In pots, they are often good outside for nine months of the year – I put mine out at the end of March and bring them in to a frost-protected greenhouse in late October.  If you only have a few, this is easy enough but if you’re like me – an addict – all the repotting and inning and outing gets a bit onerous.

I’ve recently discovered that wall pots on my south and west-facing house walls give enough frost protection for several tender Echeverias and Aloes that don’t cope with the cold and wet of winter in the ground. These are lovely but – they still need splitting and repotting!

And finally – know when to give up….