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Hardy bulbs

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Tulips.
Photo: Jardin botanique de Montréal (Lise Servant)  

Bulbs that are planted in the fall can spend the winter in the ground – they are hardy bulbs.

Purchase your bulbs early in the season, as soon as they arrive in stores, because storage conditions in garden centres and superstores are not always ideal. Choose healthy bulbs that are firm, without spots or mechanical damage.

Planting

Plant bulbs as soon as possible in the fall, or, if you must wait because of inclement weather, store them in a cool, dry place (8 to 12°C) in windowed plastic crates, mesh bags or paper bags. Be sure to label stored bulbs. Small bulbs or bulbs without outer skin are more vulnerable and prone to drying out. They should be placed in sphagnum moss, peat or sawdust.

Ideally, bulbs should be planted when soil temperature is lower than 15°C (end of September, October and mid-November), until the first frost, but the roots grow at soil temperatures above 9°C. The bulbs need time to develop their roots before the ground is too cold.

When bulbs planted too late in the fall to develop their roots, they bloom late. This is of a particular concern for narcissi, which are easily disturbed by late planting. If planted late, the roots develop in the springtime before the plant parts.

Bulbs cannot tolerate soggy soil with stagnant water; good drainage is essential. If needed, fertilize soil with well-decomposed organic material and fine gravel at a depth of 30 to 35 cm. If you plan to leave the bulbs in the ground for several years, add bone meal, which decomposes more slowly. The problem of poorly drained soil can be avoided by planting bulbs in an elevated flower bed.

It can be helpful to plant bulbs near perennials that are rarely divided and near bushes. This reduces the risk of digging them up when transplanting or dividing!

Plan to camouflage the yellowing leaves of your bulbs by planting them behind annuals or small shrubs. This way, leaves can mature without spoiling the look of your garden.

Naturalizing bulbs in grass gives the lawn a festive look in the springtime. With time, the grass will grow and the effect will be even lovelier! Many bulbs can be naturalized in your lawn, including crocus, squill, anemone, grape hyacinth and narcissus.

Among the wide array of hardy bulbs on the market, whatever variety you choose, go for the mass effect rather than just a row of flowers. Choose profusion, an abundance of flowers, too many to even be counted!

Avoid planting straight rows, which are boring and unattractive. Instead, plant your bulbs in groups. There are two ways to do this. The first is to dig a hole corresponding to the dimension of the colour you want to add to your flowerbed. After tilling the soil and fertilizing it if necessary, plant bulbs with space between them and fill the whole. The other method consists of placing bulbs on prepared soil and planting them individually to the appropriate depth using a trowel.

The distance and depth needed depend on the diameter of the bulbs. Larger bulbs are planted deeper and spaced further apart than smaller bulbs. Tilled and fertilized soil will become more compacted after planting; bulbs initially covered with 12 cm of earth will end up being 10 cm deep in the ground after levelling. The golden rule is this: The bulb should be covered with soil that is three times the height of the bulb from tip to base.

Bulbs should be planted with the tip facing upwards, except for fritillaries, which are planted on their side. Once bulbs are covered with soil, they should be watered generously. A 5-cm layer of mulch can be added to avoid unexpected warming over the winter and avoid root breakage from freezing and thawing. Finally, there are some ways to avoid damage by rodents.

Bulbs Distances
Crocus, grape hyacinth 8-10 cm
Hyacinth 15 cm
Narcissus, tulip 13 cm

Care

As soon as they are done blooming, cut the flowers off at the base. Do not remove the leaves until they have dried out and died back naturally. The leaves play an essential role in the photosynthesis process that these plants use to produce the nutrients they need to bloom again the following spring.

Based on an article by Francine Joly and Lise Lacouture in Quatre-Temps magazine, Vol. 23, No.1.

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