Contained Growing
Someone asked me what I would recommend for container growing in London which set me off on a train of thought in a number of random directions!

One of the best reasons to grow in containers is that you can cheat. Shade loving plants such as Camellias can have their day in the sun in the Spring and be moved back into obscurity when the show is over.

You can arrange and promote and demote plants in the collection depending on mood and the perfection peak of the plant in question. In larger towns and cities, more southerly counties of the UK and those on the coast taking advantage of the gulf stream, more 'tender' subjects can also be considered as 'show' plants which can be moved to shelter if necessary during the winter.

Moving plants in containers around means you can have instant scent, colour, foliage, in favourite sitting places throught the year, and create a new drama when you get bored with a scene.

Normally one thinks of container growing as either 'baskets', or those neat arrangements seen in late Autumn in the gardening magazines featuring heather, euonymous, gaultheria [i.e. evergreens] with some ivy [another evergreen] and spring bulbs. Nothing wrong in that at all. But here I am thinking about specimens possibly grown and trimmed assiduously [no not Bonsai] or left to shine on their own and grow big and lush.

Hard Labour
Be warned, growing in pots can be labour intensive, watering, re-potting, top dressing and feeding. When the root systems are well developed in summer, drying out will stress the plant and make it more prone to disease [some plants are proving tougher than others in this respect]. For example I have found that Camellia sasanqua will drop flowerbuds very quickly if it dries out.

If you are growing in pots off the ground [balconies, ledges and roof gardens] wind has to be factored in, as it can shred and shrivel leaves and make a specimen plant look tatty very quickly. Lusher plants tend to suffer more, consider plants grown near the sea which are more likely to be able to cope.

At some point the more vigorous contained plants will need some careful root pruning in Spring to limit their size.


Pests and diseases can become more of a problem when the plant is stressed. I grew a rosebush 5 floors up in London and it was stripped by sawfly and under constant attack from greenfly which I didn't expect. Vine weevils can be a major problem, non descript adult weevils [look like beetles] emerge in summer to nibble leaves and then lay their eggs, the small ginger headed white grubs then munch at the roots all winter and can kill off potted plants. Provado is recommended for control.

Compost compaction has also been a problem with certain plants - over a couple of years composts like John Innes can become solid at the bottom and waterlogged - less vigorous Hostas in particular have had problems in this environment. Make sure that there is good drainage when you plant up pots - for example some pots have raised drainage holes which can leave water stagnating in the bottom section.

As potted plants are generally watered more often they will need feeding as any nutrients in the compost get washed out after a while. I use a general purpose Tomato feed weekly through the summer.

If a plant has rooted through into the ground you can normally remove the root in late winter early spring [when the plant is dormant] - root prune a little more and replace in fresh compost. Serious container gardeners should also think of investing in pot trolleys to make moving plants about easier.

Shrubs in containers
Over the years I have grown quite a number of shrubs in pots for instant effect, for example Myrtle, Myrtus communis an evergreen with sweet slightly medicinal scented leaves when crushed and fluffy white flowers in August. Over time the cinnamon coloured bark on the trunk becomes an added bonus.

I grow Camellias in pots and am developing them as standards, they are growing slowly and that suits me - I can bring them out to shine February to May when their blowsy flowers are at their peak and enjoy them, then move them back to shady obscurity when the sun gets too strong. It also means in my alkaline soil these prima donnas can grow with their feet happily in ericaceous [acid] compost [sorry on the peat bog front, not very PC in this instance].

I am trying Skimmia in pots, Skimmia x confusa Kew Green and Skimmia japonica Kew White rather than the more often seen Rubella. Skimmia x confusa has greeney-yelllow marvellously scented flowers in early May, the early bees revel in the luxury on sunny days. When the flowers snuff out, back into the shade they go for the summer. I have recently tried a lighter compost but may go back to John Innes as the growth has been a bit scraggly recently.

I did try Rhododendron fortunei in my shady alleyway but it did become too vigorous. Then suddenly phut! A strongly growing plant just died on me after putting on a couple of lovely scented pale pink / white flowers. I am not a particular fan of Rhodos generally so cannot advise on those which would make suitable pot specimens.

Other evergreens to try ........
Pittosporum - these come in various colours, and will grow at varying rates. Small glossy crinkled leaves and insignificant looking but strongly scented flowers. The leaves come in apple greens, deep purple reds and green white variegations, worth considering for their loose airy delicacy and evergreen leaves.

If you are into trimming and primping, Box and Bay are both traditional container plants, favourites for adorning the better city restaurant and domestic doorways. A number of pots of either could be grown and moved around to make formal patterns in a paved space which you could play around with depending on mood. I sorely mistreat my Bay tree, under water, don't pot on often etc. and it still persists.

There is nothing wrong with some of the town garden staples, Fatsia japonica, great fingered glossy green leaves and supersized ivy like flowers, and laurels such as Prunus lusitanica Otto Lukyens with its daintier leaves and candles of white flowers.

If you have a cool light place protected from frost to move them for the winter then try Citrus, a reminder of Italy for me. Grown in terracotta pots in the garden in summer, the scent of lemon blossom is heady, and a tree hanging with fruit a touch of holiday glamour. Top dressed [top inch or so of soil taken out of the pot and replaced with fresh compost e.g. John Innes No. 3] every late spring and put out into the garden in late May [whenever risk of frost is over]. They go into a cool conservatory in October. I picked my first lemon in October 2002 which had been developing since November 2001 on C. limon Quatre Saisons. Citrus can be very sulky though and I have lost a few although gained a Poncirus which they are sometimes grafted on to.

Tenderish and poisonous, but scented flowers, another holiday reminder - Oleander if happy grows contained but will need some winter protection in the UK to flower well. Daturas [left] also make great specimen pot plants but need frost free protection over winter. Again poisonous but worth it, huge leaves and the most amazing downward hanging scented trumpets.

Abutilons - should be tender and are beloved of park bedding-out schemes [well at least in Bath]. They bring a lushness to summer pots. I have had two in pots in a sheltered alleyway outside by the house for over 10 years, they grow leggy and the orange lantern flowers appear late, but then I do neglect them! These two abutilons are over 7ft tall, one has a white variegation A. Souvenir de Bonn the other I bought as A. pictum Thompsonii. In a good year I re-pot in late spring taking off some of the root, adding new compost to the pot and pruning back the leggiest stems. They are fed liquid tomato fertiliser through the summer.

There is a wide selection of named abutilons including Louis Marignac, sugar pink bells, Nabob, rich deep red, Golden Fleece, flamboyant big yellow bells and Boule de Neige to name a few. Or just take your pick of un-named varieties when they hit the local supermarkets pre-packaged in late Spring or grow them from seed. Another Abutilon that is generally hardier is A indicum Kentish Belle not so flamboyant but still showy, I have not yet tried it in a pot. If you can't accomodate a big plant over winter they root readily from cuttings.

Would Eucalyptus work? very fast growing but cut to the base each Spring in a largeish ontainer, would it provide shoals of silvered airy juvenile growth year on year, may be worth a go, careful selection required - I am not an expert.

Gert lush
Hydrangeas, the suburban nightmare, but a. there are some lovely whites b. some subtle flower forms. The lace caps are gentler and more subtle than the mop heads. Although I may be developing a liking for the mop heads in the right setting [I like to pretend that my dark alleyway between kitchen and garden is a cool wet asiatic mountain forest!].

In containers you can also control the soil PH which will help gain the cooler blues in acid compost rather than more hectic pinks. Hydrangeas are often planted it seems as an afterthought but in containers at the right time they too can become real stars of the show. They can be pruned and primped rather than letting them get totally 'blobby'. Dichroa febrifuga a tenderish hydrandea relative seems to be fairly happy in a pot of ericaceous compost. It starts into flower in August and in mid November often still has indigo and mauve flower heads.

I have grown [and still do] Roses in containers, I have tried some of the larger 'old' roses but they sulked and succumbed to pests and diseases. The only happyish one which will take some drying out stress so far is Louis XIV a relatively small very deep almost black-red repeat flowering old china rose with some scent. This rose is particularly notorious for blackspot and needs spraying regularly, [so not one for the organic gardener].

If I had more room I might try a few of the other small Chinas, one I must have one day is called Spong just for it's odd name. The roses are grown in John Innes 3 compost and fed through the summer on tomato fertilser with a spring boost of pelleted chicken manure. Also watch if using JI as it can compact over a couple of years and get too waterlogged for the weaker growers.

I would like to experiment more with big leaved trees and shrubs for a 'wow' effect. I tried a golden leaved Catalpa bigniodes but it wasn't happy, too stressed in it's pot, succumbing regularly to mildew. The idea would be to cut it quite hard back when it matured to force it to send up juicy shoots with big leaves annually. There was a fantastic 'stooled' [as in cut back to the base in Spring] Pawlonia at Mells Nursery, the leaves an amazing size. Some of the species Magnolias have interesting leaves and might make good pot specimens. Sparmannia would probably do for the summer but come in for the winter. Bananas [Musa] of course - OK so they are herbaceous not trees or shrubs. I have managed to grow from seed once [M ensete I think] and don't have the space for them at the moment, they often offset quite freely. The leaves tend to shred in exposed situations though.

Fuschias - not to everyone's taste but in my shady garden they add extra flower power as we drift towards autumn, the more pendulous flowers like Lye's Unique look particularly good amongst other foliage.

Grasses, Perennials, Cacti ........
Bamboos - the designer must-have of recent times is Phyllostachys nigra 'the lack bamboo', horribly expensive but delicate tall and airy. The long stems are black, the leaves the standard green. Recently I saw some wonderful Phyllostachys aureosulcata spectabilis [I think! check out the picture on the Architectural Plants web site] in moist semi shade, fantastic thick golden yellow stems. At the RHS Garden at Rosemoor it towered over us in the moist ravine that takes you under the main road to Lady Anne's Garden. With bamboo you get the added bonus of the hisspering leaves in a light breeze. In pots it can't run and invade everything else.

Carex such as C buchananii and C testacea, New Zealand sedges would make good copper brown evergreen mops as specimen plants as would other specimen grasses. New Zealand Sedges seem pretty adaptable in pots. Phormiums - New Zealand Flax, smaller cultivars would certainly bulk up well, I have not tried in pots, the big one's would get way, too big but would certainly have that wow effect!

Agave - for a bit of oomph! and not cheap for a big specimen, these spiky, succulent creatures look very formal and 'architectural' in pots. They generally require some protection in the Winter and are particularly vulnerable if snow or winter wet gets into the crowns as I have found to my cost. Or Aloes [see right at the Oxford Botanic Garden].

Kniphofia northiae - I saw this in a pot in a garden some years ago and thought wow! The flowers are not particularly pleasing but the foliage is really chunky and bold.

Cactus - more shapes and forms. I have a gangly Opuntia robusta [a type of prickly pear] that goes out in the summer and takes the risk of slugs and snails and rainy cool weather. Maybe one day I will get flowers? Also Aeoniums look good, Schwarzkopf is well known with black leaved rosettes making a leggy tree-like plant, for full sun. They are easy from seed and fast growing so why not try them and see what you get?

Hostas in pots - my last resort against slugs and snails and the leaves do seem to last longer. I have not tried vaseline or copper strips around the rim of pots as an added deterrent.

The Hostas I have don't seem to mind being a bit under watered, and at their peak are a fantastic show, dying down again in autumn. My favourite has to be Hosta plantaginea, apple green glossy leaves and scented white flowers in September, elegant and cool. Fried Green Tomatoes is another scented hosta with large open pale lilac flowers in August. Sum and Substance has large gold/green leaves and looks fabulous in a pot.

Ferns - specimen ferns look cool and lush, I am still experimenting. Blechnum chilense makes a big bold evergreen statement and as an acid lover has to stay in a pot in my garden anyway. So far Osmunda regalis is also doing quite well in a pot kept moist and in semi-shade. The scent of a crushed frond as you brush past is very evocative. The airy bronzy fronds of the evergreen Dryopteris erythrosera would also look elegant in the right setting as might Athyrium niponicum the Japanese Painted Fern.

Impatiens omeiana - much better in a pot as a specimen plant than in the ground. The silver leaves to the left are Begonia hatacoa Silver, during the summer you can play around with indoor plants outside for vivid effects.

Bulbs, corms & ..
Agapanthus - Nile lilies, I am still experimenting with these, some are evergreen some not. In theory large juicy blades of green send up long thin stems topped by blue [varying from sky to purple blue] or white, mops of bells in July. Slightly tender depending on where in the country you are located and depending on species.

I have A. Purple Cloud which is evergreen and has so far not flowered [snow covered it two years ago to the detriment of the main 'bulb', the younger bulbs are now bulking up]. I also have A. Sandringham - deep rich blue [deciduous] and A. Golden Rule, with gold edged leaves and pale blue flowers [deciduous]. I have grown A. africanus from seed, these are now a good few years old and in pots, but are not showing any inclination to flower yet. I am also not totally convinced about the keep them underpotted to make them flower rule either - jury is out on this piece of advice.

Lilies - a must-have in pots, the ultimate July luxury, Lilium regale, high summer personified. Then when just a bunch of leaves again, hide them somewhere to bulk up the bulb. I have found that if the compost dries out significantly when the buds are forming they will drop off - no flowers that year!

Hedychium - Ginger lilies, fantastic for foliage, big paddle leaves are late risers from a knobbly knot of rhizomes. I grow H spicatum which overwinters if kept dry under some shelter. In late summer it produces small short-lived spidery white flower spikes [slightly scented]. H. densiflorum Assam Orange [left] is OK, not as showy, small orange spikes and no scent, but makes up for it to some extent with the exotic paddle leaves, finer than H spicatum. H. gardnerianum is the ultimate luxury if you can give it a long enough growth period, huge yellow touched red cones of heavily scented flowers. Cannas in pots would give a similar lush leafy effect with good compost and feeding.

And I could not do without my small pots of early Spring bulbs, Iris danfordiae, Iris reticulata, early and mid season daffodils such as N.February Gold, Hawera, Baby Moon, and N caniculatus. And later in May watching the colour flush gently up tulip petals and smile with them as they open up to the warming sun. The pots can be hidden away after flowering, the spring performers can lose their foliage disgracefully and scruffily in peace, plumping up their bulbs for next year's show * as they make way for the next star performer. Some tolerate container growing better than others in terms of repeat performing the next year, you may need to treat some bulbs as an annual and replace yearly.

I have grown some veg / fruits in pots in particular tomatoes and peppers. Pictured to the right is Tomato Peacevine and Crocosmia Saracen [in separate pots]. A classic fruit for pot culture is the Fig - they are tolerant of some benign neglect.

Annual climbers - add height and flower power. The old fashioned smaller flowered Sweetpeas including Matucana [purple/ lilac bi colour] work in large pots, keep moist and fed. Ipomea, Morning Glories and Spanish Flag trained up canes or a support will provide later colour. If you have a greenhouse annual climbers can be started earlier and put out after all danger of frosts have passed to get the show going earlier.

* Iris Danfordiae tend to disappear completely never to be seen again, but has such welcome early and cheerful little yellow flowers it is worth growing again and again, I wonder how it copes in the wild?

@Kari's garden 2008