Monty Don: Sleeping beauties (2024)

I would imagine there has been a frenzy of excitement down at Observer Towers with the new format, new year, new mood of energy and hope, but these things have quite passed me by here in the sticks. But things are stirring in the undergrowth, alas, in exactly the same format that they have boringly persisted with for the past millennium or so. The snowdrops are still green bullets piercing frozen soil, but it won't be long before they flower, with aconites close behind them. Over the next three weeks I shall be focusing on growing bulbs for every season, and now is a good point to start, when the early spring bulbs seem a possibility rather than a promise.

Bulbs are packed with flowers. That is their magic, especially in spring when flowers are scarce. In fact, it takes well into June before flowers start to dominate over foliage, so a bulb, however small, can provide pure colour, be it the blue of scillas, the gold of daffodils or the whole rich palette of tulips. Planting bulbs is all about setting a detonator for colour, and anyone can put that explosion where they want it, and with a little experience, research and selection you can also time it for pretty much when you want it.

Let's start at the beginning. 'Bulb' is a generic word to cover those plants that store their next season's flower and the nourishment to grow it within a self-contained capsule that can survive until the following growing season without nutriment or roots. The true bulbs - such as tulips, alliums, Iris reticulata I unguicularis and daffodils - are essentially a very reduced stem made from concentric layers of fleshy scales with a dry, protective outer layer. Each scale is either the base of a leaf or the thick-scale leaves that never appear above ground. The paper outer layer is the remains of last year's scales. Bulbs tend to be smooth and, er, bulb-like. However, some bulbs, such as lilies and fritillaries, have no protective skin and the scales are separate. There are three distinct forms of bulb. In the most common - such as tulips or alliums - the bulb shrivels and dies after flowering and is renewed from buds formed at the base of the scales at the point where they join the basal plate. Narcissi, on the other hand, do continue year on year, producing offsets rather than wholly renewing themselves. This is why you get ever-increasing drifts of vigorous daffodils, but tulips tend to increase more reluctantly and with a marked loss of vigour as it takes two or three years for most tulip bulbs to flower. The final type of bulb, such as Hippeastrum (amaryllis), has embryonic bulbs for three years ahead within each 'parent' bulb - so it is genuinely perennial.

Then there are corms, like the iridaceae family - which includes iris, gladioli, crocus, crocosmia, freesia and dierama - which form themselves anew each year on top of the old one, looking like an unwrapped packet of fruit pastilles, as corms are all distinctly flattened on the top and bottom. They are also wrapped in a dry, protective layer of old leaves. They make cormels - mini corms - as offsets during the growing season; these can be separated and planted out without damaging the parent corm and are a very good way of propagating the plant. Corms, such as erythroniums, develop as offsets so the colony can spread while the parent grows larger each year.

Tubers differ from bulbs and corms inasmuch that they are not the base of the stem but the swollen roots that are used for food storage - unlike most roots, which are solely a medium for conveying food to the plant. The old tubers die after flowering and new ones are formed throughout the growing season, which is why you should never lift or cut back a tuberous plant, such as a dahlia, until all growth has finished for the year. Tubers are found in some orchids, in dahlias, anemones, corydalis and in cyclamen species, as well as, of course, the potato.

Finally there are rhizomes, which are swollen underground stems, usually horizontal, always very shallow (sometimes on the surface of the soil). The best-known examples are bearded irises, Anemone nemorosa and lily of the valley, as well as ginger and couch grass.

In an ideal world, the best time to plant bulbs is when they are dormant between accumulating energy for next year and starting growth. But ideal times tend to either take us unprepared or ringed round with smugness. I have been doing this sort of thing for well over 30 years and have not mastered the ideal timing yet. The truth is that it is not too late to plant spring bulbs - but get on with it. Tulips are very comfortable with a January planting, but crocus and narcissi are likely to do better in their second season than first if planted later than November. Snowdrops and aconites are much better planted 'in the green', by lifting and dividing existing plants just after they have finished flowering - which in most cases will be early March. If you plant them as dry bulbs the failure rate can be horrendous.

The general rule for planting all bulbs is to go rather deeper than the obvious. Two or three times the depth of the bulb itself is the usual guide, although that means too much measuring for me. The guiding rule is that you will do less harm by being too deep than too shallow. However, do not agonise over this. Plants are always tougher than you think.

The other general rule is that bulbs need good drainage and this is vital for ones like tulips, alliums and Iris reticulata. The best way to ensure this is to mix loads of grit into the general area or container (50:50 grit to potting compost is none too gritty) they are to be planted in, or to add a good dollop of grit in every planting hole. Tedious but worth it. Some spring bulbs, such as snowdrops, fritillaries, eranthis and, in my own garden, muscari seem to thrive in quite damp conditions. But all these like a humus-rich, fairly free-draining soil.

All bulbs look good in a container, particularly terracotta pots. These can be moved into sunshine or shade as required and can also be guaranteed to provide the right kind of drainage. Pack smaller bulbs in tightly and try and find shallow alpine pans, which are the perfect container for crocus, snowdrops, fritillaries, iris, muscari and other small bulbs. Remember that most will need a summer baking so make sure they have some sunshine when dormant.

Ideal soil conditions

Bulbs

Daffodil well-drained