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Planting Bulbs This Weekend?
October 16, 2005

It's that rare, magnificent autumn day, and you want to take advantage of if by planting all of your spring-flowering bulbs, today.

The following ten tips will guarantee the success of your afternoon's venture:

When should bulbs be planted?

As a rule of thumb, it is recommended that spring flowering bulbs be planted when the temperature of the soil is around 13°C. In some parts of the country this could be late September, in others, mid-November.

If soil temperatures are too warm, the bulbs can be harmed by soil fungi. The disadvantages to planting in late November or early December are: you can find yourself with rain and really cold temperatures –– conditions that take the joy out of working in the garden; and, chances are that the bulbs won't have time to establish root growth before the ground freezes solid.

Do any bulbs have to be planted immediately?

Certain specialty bulbs should be planted immediately after purchase, if not, they can dry out and die. This applies to all varieties of Erythronium (dog's-tooth violet), Corydalis, and Fritillaria. Snowdrops, also susceptible to drying out, should be purchased early in the season, and planted immediately.

Can bulbs really withstand the winter cold?

In regard to this question, we're lucky in Canada. Many spring-flowering bulbs, such as: tulips, hyacinths, narcissus, iris, crocus, grape hyacinths, scilla species, anemone blanda, the entire Allium family, and many other varieties, actually need a certain amount of cold in order to produce flowers.

Where should bulbs be planted?

Bulbs are suitable almost everywhere in the garden. In beds, in borders, in rock gardens, among perennials –– you name it, and there's a bulb flower that will look fabulous in that spot. If you're using bulbs in borders or rock gardens, pay attention not only to the flower of the bulb, but also its height, shape and the look of its foliage.

The giant onion (Allium giganteum) , for example, can look like giant, fluffy, purple exclamation marks when planted here and there in borders. On the other hand, some of the earliest little bulbs, such as crocus, snowdrops and iris reticulata look terrific planted right in the lawn.

How deep should bulbs be planted?

Regardless of what bulb packaging might say, in Canada it is recommended that bulbs be planted three times as deep as the bulb is tall. This depth, will generally protect bulbs from late winter thawing and refreezing, which is one of the biggest threats to the success of bulb flowers.

The distance between bulbs depends on their size, and the size of their flowers. Be sure to plant the little ones at least 5 cm. apart, medium sized ones about 10 cm. apart, and the large ones a good 20 cm. or more from one another.

Does the soil require any special treatment before planting?

It is always a good idea to loosen the soil under the bulb before planting. This allows air to penetrate the soil, makes it easier to work, and will allow excess water to drain off easily. This loosening should be done right before planting. If heavy rain is expected with a day's time, it would be advisable to wait. Heavy precipitation can muddy the soil which risks asphyxiating the bulbs.

Can bulbs be planted in any kind of soil?

Not every kind of soil will yield truly fine results. Dry acidic soil isn't great, and heavy river clay is a difficult soil to dig out for making holes in which to plant tulips and narcissi, although they will thrive there. Bottom line is that bulbs do best in well draining soil.

How much water can bulbs tolerate?

Under certain circumstances, too much water can seriously affect the emergence of bulbs, corms and tubers. This applies not just to the time immediately after planting, but also if the soil freezes up again after a brief thaw. Low-lying gardens where water tends to accumulate are less suitable for bulbs. However, once the plants emerge, excess water is no longer a problem.

Should spring-flowering bulbs be lifted after they flower?

In a word –– no. In Canada, because of our cold winters, almost all spring-flowering bulbs are perennials. This means, that they will reliable come back for three to five years. Others, such as grape hyacinths, snowdrops, crocus and others, will naturalize, which means that they will grow in numbers over time.

The key to success with bulbs, is, after flowering, to allow the bulb foliage to naturally wither and die. Do not tie, bunch or braid the leaves, as it is through the process of photosynthesis that the bulb is replenished for next year's blooms.

What could possible go wrong?

In spite of the best laid plans, things can still go wrong. If nothing at all emerges, the bulbs have usually rotted. In such cases, all that will be left of them are their decayed remains. The reason for this, is most likely prolonged wetness that even with proper drainage is sometimes unavoidable.

If the leaves emerge, but no flowers appear, perhaps the bulbs were not stored at the proper temperature after lifting, were subjected to late summer heat waves at the garden centre where they were purchased or in your garage before they were planted. Another cause for leaves but no flowers is if you have applied a nitrogen-rich fertilizer to your lawn and the bulbs caught some of the fallout. Nitrogen is great for green things, but not for flowers.

All in all, bulbs are exceedingly simple to work with. Dig a hole. Plop in the bulb (pointy side up). Fill in the hole. Water. Wait for spring.


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