Gardening: Go lush, go dense with winter evergreens
A generous pot of trailing and upright evergreens will create a pleasing lushness in the winter garden
Pinus mugo ‘Carsten’s Wintergold’ a slow-growing conifer that is a great choice for a winter container. Photograph: Richard Johnston
In the damp grey gloom of an Irish winter’s day, we need things in our lives that make our hearts sing. Winter pots are just the ticket, their subtle but defiant beauty a reminder that even at this time of year there is much pleasure to be gleaned from the garden. How to make them shine brightly? The trick to creating the perfect display is to (a) use great-looking containers (b) plant densely, as even the hardiest and most vigorous of species will make little or no growth during the dark, cold months ahead (c) choose species/ varieties whose decorative qualities belie the fact that they can stand up to the rigours of an Irish winter and that also (d) offer at least one of the following qualities: evergreen foliage, ornamental berries, pretty flowers, outstanding architectural form and/or textural interest.
Yes, I admit that’s rather a lot to ask for, but the good news is that one of the most important rules of gardening – carefully considering any plant’s eventual height and spread – goes out the window when it comes to winter pots. Instead we can treat them as beautiful props on a temporary stage performing a brief but important starring role. Once too large or no longer required, it’s a simple matter of transplanting them into a more permanent position in the garden or giving them away to an appreciative friend.
Let’s begin with the containers, which can make or break a display. The best are handsome, well-made, frost-proof, have drainage holes, are wide enough at the base (at least 25cm) that they won’t topple over in a winter gale and large enough to protect vulnerable root systems from drying out or being damaged by sub-zero temperatures. Using pots of varying heights and sizes but of a similar design, colour and shape will also give the finished display visual coherence and avoid it looking cluttered. Bear in mind another golden rule of container growing: one generously-planted, elegantly-designed large pot will always be a hundred times more impactful than a mean huddle of small ones. It will also require less maintenance.
The best growing medium? Use a soil-based John Innes compost as it’s heavier (for extra ballast) as well as less likely to dry out than soilless composts. For this reason it’s a good idea to roughly place any containers in their final position before filling/planting makes them too heavy to move easily. Speaking of which, give some careful thought to the spot you select, which should be chosen for maximum impact and to give you maximum pleasure as well as to keep your plants as happy as possible; ideally this means a sheltered position by a often-used doorway or entrance or in view of a main window.
As for the planting, it’s hard to overstate the key role that foliage plants play in any winter container display, which is to provide long-lasting seasonal interest and act as an essential leafy foil to any brighter pops of floral colour. Choose a mixture of trailing and upright evergreen species and you’ll create a visually satisfying plant combination that will soften the hard edges of containers and create a pleasing lushness. Evergreen trailing or spreading plants suitable for the role include any of the more compact, smaller-leaved, trailing ivies such as Hedera Goldfinch, H Ivalace or H Midas Touch , vinca and varieties of creeping bugle such as the bronze-leaved Ajuga reptans Blueberry Muffin. Examples of evergreen plants with a more upright or clump-forming growing habit suitable for a winter container include shrubby species such as box (Buxus), skimmia, holly (Ilex), hebe, Viburnum tinus, sarcococca, Euphorbia x martini, winter heather (Erica), slow-growing/dwarf conifers including Tsuga canadensis Cole’s Prostrate and varieties of PInus mugo, fatsia, Gaultheria procumbens (prized for its scarlet winter berries), leucothoe and pieris (the last four prefer an ericaceous compost).
Evergreen or semi-evergreen perennials that look great in any winter display include hellebores (examples include Helleborus argutifolius, the exceptionally long-flowering H x sahinii Winterbells, H sternii and H x orientali, all semi-evergreen except in very cold gardens); heuchera and heucherella (these shade-tolerant foliage plants are also semi-evergreen in all but the coldest gardens and are available in a wonderful range of foliage colours, including some two-toned varieties such as the burgundy-and-silver Heuchera Silver Scrolls and chocolate-and-lime/ gold-and red Heucherella Solar Eclipse), as well as evergreen ornamental grasses including Carex testacea, Carex comans, Carex oshimensis Evergold. Everglow, Everillo and Everest, the black-leaved Ophiopogon planiscapus Nigrescens and evergreen ferns such as Polystichum setiferum and Polypodium vulgare. The ornamental bare stems of shrubby, deciduous plants such as dogwoods (varieties of Cornus alba and Cornus sericea) and the contorted hazel (Corylus avellana Contorta) also look great used in large containers or tubs. Whichever plant combination you plump for, choose it with a colour theme in mind (for example, silver and white, or bronze with marmalade-orange and russet-red), and keep the use of variegated plants to a minimum to avoid it looking too busy.
If you find yourself longing for some pops of vivid colour, then tuck in some winter bedding (violas, polyanthus and cyclamen are good for mild, sheltered gardens) while a sprinkle of compact, late winter/ early spring flowering bulbs (examples include crocus, eranthis, dwarf daffodils, anemones, snowdrops, muscari) will keep the show on the road for many months to come.
This week in the garden
The recent plunge in temperatures has blackened the foliage of dahlias, a sign that it’s time to cut the plants right back and either cover the ground above their fleshy tubers with a thick, protective winter mulch of autumn leaves, straw, garden compost or bracken (suitable for milder gardens) or (for colder, wetter gardens), gently dig up the tubers, shake off the excess soil and store them in a cool, dry, dark, frost-free spot until next spring. Try to make sure that all tubers are clearly labelled during this process to avoid confusing the different varieties next year while replanting.
Gather fallen leaves of deciduous trees and shrubs and place them in a black bin bag (with a few holes pierced in it) or a wire cage. Placed somewhere cool and dry, these will slowly rot over a couple of years to make lovely crumbly leaf mould, an excellent, planet-friendly soil conditioner that can be used as a wonderful addition to borders/ shrubberies or added to homemade compost. The leaves of beech, oak, alder and hornbeam are amongst the best to use for this purpose, rotting easily into a rich, dark crumbly mixture. Those of horse-chestnut, sycamore and walnut are slower to rot and should be shredded or chopped up with a shears before adding them to the pile
Do this: Grab the chance to see Hedgerow: Stories from a linear world, the latest exhibition by the Irish botanical artist Yanny Petters on show at the Olivier Cornet Gallery on Dublin’s Parnell Square until Sunday, November 10th. Petters, who has described her work as being “inspired by the minutiae of nature… the detail, colour and form within the realm of plants and their environment”, celebrates the role that our hedgerows play in supporting biodiversity, reducing soil erosion and providing valuable shelter as well as their complex seasonal beauty and ancient history as part of the Irish landscape. See oliviercornetgallery.com and yannypetters.net for details
Dates for your diary: Tuesday November 4th (7.30pm), National Botanic Gardens, Glasnevin, Dublin 9, Orchid Trade; an overview of the legal complexities and a guide on how to be a responsible consumer, a talk by botanist Dr Noeleen Smyth on behalf of the Irish Orchid Society, see botanicgardens.ie; November 7th (8pm), Artane Family Recreation Centre, Kilmore Road,Artane, Dublin 5, a talk by dahlia expert Alick Brannigan on behalf of Dublin Five Horticultural Society, admission €5, call 0872423020 for details; November 13th (8pm), Kill O’The Grange Parish Centre, Kill Lane, Dún Laoghaire, Co Dublin, Roses Revealed, a talk by author and broadcaster Dermot O’Neill on behalf of South County Dublin Horticultural Society, admission €5.