Naturalizing bulbs

by Dale Odorizzi, Lanark County Master Gardeners

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Naturalizing bulbs is planting informal "drifts" of dozens or even hundreds of bulbs among other plants. With time, the bulbs multiply and spread into a spectacular display of flowers with minimal work and minimal damage to your budget. Lightly wooded areas, lawns, and rock gardens are the most popular places for naturalizing.
More gardeners embrace naturalistic gardens and embrace naturalizing bulbs. Lawns have become the spot of choice for naturalizing many smaller bulbs including crocuses, scillas, Spanish bluebells, grape hyacinths, and snowdrops. Small early bloomers are also well suited to lawns because they grow about the same height as the grass. Their foliage conveniently browns and ripens right about the time a first mowing is necessary, though you'll probably have to let the grass get fairly long before you can cut it. The foliage on nearly all bulbs must be allowed to brown thoroughly before removing, because it replenishes the bulb for next year.

Larger, later bulbs, such as daffodils, don't ripen until the grass is quite high. This isn't good for the grass and doesn't give the neat look many homeowners want. Instead, plant daffodils along a fence where the grass can grow very long into late spring as the foliage ripens. If the turf is very thick and very healthy, it may hinder the spread of some bulbs by acting as a living mulch.
Bulbs naturalize just about anywhere. A classic combo is spring-blooming bulbs under deciduous trees, particularly in woodland areas or under a large tree. The bulbs bloom before the trees leaf out, so they have plenty of sun while actively growing. If your trees have shallow root systems, plant some of the smaller bulbs, which seldom need to be planted more than four inches deep and often can be planted as shallowly as two inches.

Fields and meadows are a traditional place to naturalize bulbs. Most bulbs are natives of mountainous areas with arid summers, so it's critical that any meadow or open grassland isn't too soggy and that you don't plant in moist, low-lying areas. Bulbs require excellent drainage and can easily rot in wet summer or autumn conditions. Because drainage is so important, slopes and rock gardens are other ideal places for naturalizing. This makes them an unconventional but beautiful addition to drought-tolerant prairie plantings as well. They also love sandy and gritty soils.

Planting bulbs for naturalizing doesn't vary much from planting bulbs elsewhere except that you'll be working around other elements—turf, roots, existing plants. If your site is riddled with tree roots, it's a good idea to stick to small bulbs that don't have to be planted more than two to four inches deep. When planting bulbs in a lawn, there are two ways to proceed. One is to peel off the turf with a flat-edged spade and then plant underneath. As long as the turf is not allowed to dry out completely, it will reestablish itself. The other way is to punch holes in the turf and plant bulbs individually. This disturbs the turf less but can make planting more difficult since you have to hack through grass.

Some varieties of daffodils are sold particularly recommended for naturalizing.

It's always a good idea to work in some compost or a handful of bone meal at planting time, bulbs suited to spreading should be able to cope with the existing soil on their own. Still, the looser the soil the better, so if it's easy to add compost/bone meal, do it at this time. Another alternative is to fertilize the bulbs as they are dying off, particularly if the bulbs have been in the same position for a long time. 15-15-15 is a good choice, or any all-purpose fertilizer. Mix it in a watering can and go round and water each clump of bulbs. Particularly do this to any group of bulbs that are appearing but are not flowering, ‘blind’ is the horticultural term.

Generally, you need to plant bulbs, in shade or full sun, before your area's first hard frost— September or October in our area. Well-drained soil is the crucial factor, along with choosing bulbs appropriate for your area for naturalizing. Find sites for them that showcase their wild charms, and enjoy a spring-after-spring celebration of natural gardening at its colorful best.

Wherever you decide to plant your bulbs, the experts agree that it's important to get the best bang for your buck by planting en masse. You want enough of a concentration that it's showy. And no planting in soldier-straight rows, either. This is naturalizing, after all. Plant in large, tapering drifts. Or simply toss the bulbs on the ground and plant them where they land.
The best thing is, once established, naturalized bulbs completely fend for themselves, and the rewards of your effort will pay off for decades. Plant bulbs in the right spot and they'll spread into ever-widening pools of beauty.

For any gardening information phone Ankaret Dean at 613-278-1293.