Hartley Magazine

All the latest news, hints, tips and advice from our experts

Forcing lily of the valley in the greenhouse

The weather may be cold and grim and the days short and unpromising, but a great use for the greenhouse in these colder months is to use it to bring on some early spring flowers. They bring with them that whisper of warmer, lighter, more hopeful days to come, and even the act of planting them helps us to remember that this dark spell will not last forever. The shelter and extra warmth that is given by the greenhouse will naturally encourage spring bulbs to grow faster, and flowers to appear earlier, and we can use that to our advantage. Tiny iris reticulata, Iris danfordiae and Iris histroides are all brilliant for this, alongside crocuses and other compact spring bulbs, but ideally all of them needed to be planted last autumn. But there is one particularly lovely plant that it is not too late to force. I love to plant lily-of-the-valley in my greenhouse, for flowers in early April, and there is still plenty of time to plant them for early flowers. In fact it isn’t quite time yet, but you do need to be ordering them now for delivery in late February and early March, and be ready for immediate planting then. You are looking to buy ‘pips’ – bundles of roots each with a little shoot. You should also be looking for your pips to be ‘pre-chilled’, which means that they have been put through a good thorough cold spell which will have fooled them they have been through a good, hard winter (as this one has not been, so far) and that spring is coming and it is now time to grow and to flower.

Lily of the valley pips ready for planting and forcing in the greenhouse.

They arrive as bundles of roots with little shoots and you plant the roots deep into a pot with the shoots just proud of the soil. You will want to choose a nice pot here, ideally an old, weathered terracotta one because as soon as they are in flower you are going to bring them indoors to flower on display and a shiny, new plastic pot doesn’t look great. Settle the soil well around the roots, label the pots, water them, place them somewhere sheltered and warm, and forget about them. From time to time they will need a little dribble of water and then as soon as they start to grow well they will need watering well and regularly.

When flower spikes start to form, bring them indoors to flower. Small, pure white, bell-shaped flowers hang from elegant green flower spikes and fill the house with their delicious spring-like scent. If you don’t want them indoors place the pots on a table or steps outdoors where you will pass them regularly, ideally at nose height so that you can get your nose down to them regularly.

Though forced plants should flower earlier, lily-of-the-valley is associated with May Day and in France, where they are called ‘Muguets’ it is a traditional to buy a bunch of ‘Muguets de Mai’ on the 1st of May, and to wear a small bunch in your lapel, where the scent will drift up to you. After your forced plants have finished flowering you can plant them out in your garden or into large pots or troughs and in subsequent years they will spring up again and will flower around the beginning of every May. Be wary: they are very strong growers and spreaders and are maybe better for large woodland gardens than they are for small urban or suburban ones, unless you only want to grow lily-of-the valley… However you can confine them to a large container very well, and get the benefit of those beautiful scented flowers every spring.