Toronto
Master Gardener Factsheet 
Toronto Master Gardeners are trained volunteers dedicated to providing horticultural information to the public.
For answers to horticultural questions contact the Toronto Master Gardeners' Info Line at the Toronto Botanical Garden (416) 397-1345 (Mon. to Fri. 10 a.m. to 1 p.m and Sat., Sun. and Holidays noon to 3 p.m.) or our web site.
Links
 |
 |
 |
 |
 |
Toronto Botanical Garden is a volunteer-based, charitable organization whose purpose is to inspire passion, respect and understanding of gardening, horticulture, the natural landscape and a healthy environment.
777 Lawrence Avenue East
Toronto, ON M3C 1P2
Tel. 416-397-1340
Fax. 416-397-1354
www.torontobotanicalgarden.ca
Bulbs for Naturalizing
Spring flowering bulbs add colour and interest to an area as they often bloom earlier than other flowers. Some add fall colour. Bulbs listed below include those grown from true bulbs, corms, rhizomes, tubers and tuberous roots. They are considered together because all of these plants are produced from swollen storage organs and all have the ability to naturalize, spreading readily from a single plant into many plants over time. This fact sheet provides information related to choosing and growing ornamental bulbs that naturalize.
Plant bulbs in grass, meadows, in beds amongst later blooming plants, or around the base of deciduous trees. The chosen location should provide enough room for these plants to colonize.
If you mow your lawn frequently use early flowering spring or fall flowering bulbs. The grass grows more slowly in the early spring and fall so the bulbs and grass do not compete as much for nutrients and water. During this time the lawn does not have to be mowed as often thus allowing the leaves of the bulbs to mature. Leaves supply the bulb with nourishment that will enable growth the following year and generally should be left untouched for six weeks. However, a few small bulbs complete their life cycle more rapidly (e.g. Eranthis byemalis, Chionodoxa, Scilla, Crocus and Galanthus). A shortened life cycle allows the grass to be cut within one month.
Plant large leaved bulb plants where the leaves will be hidden as they die down, particularly if used in an ornamental bed.
As a general rule bulbs should be planted at least two to three times the diameter of the bulb. This can vary with soil type. In heavy soils that are not amended it may be better to plant bulbs more shallowly and in light soils it might be wise to plant them more deeply. In colder areas plant more deeply and mulch.
Make sure that bulbs are not planted in wet soil. After flowering bulbs need drier conditions and often excess moisture, necessary for other annuals and perennials in a border, may affect the development of next year's flower buds, at the time when the bulbs should be drying out.
At planting time you can add bone meal (a natural phosphorus product that is mild and slow acting), or a product called “Bulb Starter”, obtainable at a nursery, or a chemical fertilizer high in Phosphorus (the middle number). It is a good idea to water if the soil is unduly dry.
Bulbs may be hand tossed and planted where they land to create a natural effect. It is not wise to do this with small bulbs, as they may be lost, nor is it wise to do this with a large number of bulbs because this can result in a haphazard planting with little visual appeal. .
For larger numbers remove a strip of turf, place a group of small bulbs on the soil and recover them with the turf. Larger bulbs should be planted more deeply using a trowel or bulb planter either where the turf has been removed or directly through the turf.
Plant bulbs in groups to produce a solid block of colour. Avoid using too many different varieties in one location because this can create a somewhat chaotic effect.
Light conditions will vary but bulbs will not thrive in dense shade. Check preferred light conditions when choosing a bulb. The preferred light condition is noted for the species listed below.
Bulbs prefer a loamy well-drained soil but conditions must not be overly dry. Waterlogged soil leads to rotting of the bulb. Never plant in newly manured soil as the acidity in the manure could burn the newly emerging roots and shoots. If the soil is clay based amend it by adding coarse sand and/or compost to improve the drainage.
Because bulbs are often planted in 'natural' or less formal locations their maintenance is similar to growing bulbs in the wild. No maintenance is necessary for these bulbs, assuming that their leaves are allowed to die down naturally.
Strong and healthy bulbs are less likely to produce plants that succumb to bacterial and fungal infections. Healthy plants are also more able to withstand attack by pests. When buying a bulb make sure it has no soft spots, is hard to the touch and has no outward signs of physical damage.
Colour, height and form are personal choices. If you are naturalizing in a mowed lawn choose early, small spring flowering bulbs. If you plan to plant an uncut meadow larger, bulbs, such as Narcissus species, may be chosen. If you plan to plant in a sunny border you may wish to choose bulbs that will die down quickly or can be easily hidden by later emerging perennials (see comments above related to smaller bulbs). If you wish plant under a deciduous tree, choose bulbs that flower early before the tree leafs out, or choose ones that tolerate semi shade conditions.
Bulbs used for naturalizing rarely have disease and viral problems.
Large pests such as squirrels, moles, voles, cats, dogs, and deer can be a problem. There are many recommended remedies. To repel rabbits sprinkle Blood meal over areas where bulbs have been planted or have sprouted. This is a nitrogen fertilizer and quite harmless but this can attract carniverous animals. Cayenne pepper can also be used but is an irritant to eyes and other mucous membranes of animals or humans. Both of these substances have to be replenished after rain.
Metal or plastic screening or mesh, often the most effective deterrent, can be placed around the bulbs or on top of the ground after planting, to prevent animal damage. Fishing line, strung around the planting area, fencing of adequate height or tomato cages placed over plants, may deter deer. There are also commercial products sold as deterrents for deer.
N.B.: The City of Toronto adopted a new municipal by-law (spring 2004) that restricts the use of pesticides. For details about the by-law visit the Pesticide by-law page on Toronto's Public Health's Web site at www.city.toronto.on.ca/pesticides or www.toronto.ca/health. Questions may be e-mailed to pesticide@toronto.ca.
Following is a list of bulb plants that naturalize. The type of bulb, time of bloom and preferred light conditions is provided.
Factsheets are produced by the Toronto Master Gardeners in association with the Toronto Botanical Garden. They provide introductory information about a broad range of horticultural topics and are intended for personal use and study purposes. Should your gardening group or organization wish to use multiple copies we ask that you inform the Toronto Botanical Garden at info@torontobotanicalgarden.ca.
Date revised: November 17, 2007
