The time of the season: Looking at early and late bloomers

Many bulbs bloom in springtime — those bulbs are the most familiar and beloved to gardeners in cold-winter climates. However, fewer but no-lesspretty ones make their show in summer or even fall. See the next section for examples of these types of bulbs.
The terms early, mid-season, and late abound in bulb descriptions. All this naming system means is that some bulbs burst forth earlier rather than later — all during the springtime. A month or more of time can separate the first snowdrop from the first tulip or the first tulip from the last tulip. The expected bloom time is worth knowing so you can plan for continuous color or set up nice color duos or spectacular full-bed shows. The reason people plant most spring-blooming bulbs in the fall is not just so the plants can get a head start on root growth. These bulbs also need a period of cold (so obligingly supplied by a winter in the ground) to maintain their biological clocks. The warmer, thawed-out but moist soil of spring, not to mention the warm sun above, coaxes them at last to burst into their full and glorious potential. In mild-winter regions, gardeners can buy some bulbs pre-chilled (these plants have a limited selection compared to all the springbloomers), or gardeners can refrigerate regular bulbs for a specified period (at least eight weeks) and then plant them in late winter or early spring.

Defining terms: Bulbs aren’t always, well, bulbs

When you shop for garden bulbs, you may immediately notice some variations on the underground-storage theme. The minor but key differences are worth knowing because they affect not only what sort of plants the bulbs produce but also how to divide them to get more plants. Here’s a rundown of some of the plant structures that gardeners call bulbs:

• True bulbs: Bulbs are composed of concentric fleshy scales, or layers, which are actually modified leaves. Yes, just like an onion. At the base of a true bulb is a basal plate, the place from which the roots grow. Examples of true bulbs include allium (flowering onion), amaryllis, daffodil, hyacinth, and tulip. Interestingly, when you cut a bulb in half, you can see the future plant parts — stem, leaves, flowers. Offsets that you can pry off and plant may appear. In some cases, notably with lilies, you can grow new plants from individual scales.
• Corms: These structures resemble true bulbs somewhat, with a growing point on top and a basal plate at the bottom. However, they don’t have the clasping modified leaves; technically, corms are swollen underground stems. Also, they use up their store of food in one growing season — though new little cormels (baby corms) often appear atop the old one to carry on. Examples include autumn crocus, crocus, crocosmia, freesia, and gladiolus.
• Rhizomes: Rhizomes are thickened stems that grow horizontally; the roots grow down from the underside. The tip tends to have a primary growing point, though productive side-buds are common, and you can cut them off and plant the buds individually. Examples of rhizomes include agapanthus, bearded iris and many other irises, canna, and lily-of-the-valley.
• Tubers: Tubers are swollen stem bases. Roots grow from their sides as well as their bases, and you may see multiple productive buds. A classic example of a tuber is the potato. Other examples include most anemone, tuberous begonia, caladium, cyclamen, dahlia, and gloxinia. The way to divide tubers varies by the type — dahlias, cyclamen, and gloxinia involve different methods. Generally, you want to cut the tuber so that each piece contains a bud.
• Tuberous roots: These structures are in fact roots, not modified stems. Fibrous roots, like fingers, radiate outward from a central point. You can easily divide these roots to get more plants, making sure, of course, that each piece has at least one bud on it. Examples include alstromeria, clivia, eremurus, and ranunculus. Many gardeners discuss the differences between hardy bulbs and tender bulbs. Unfortunately, making the distinction isn’t easy, because a tender bulb in one climate (like Zone 4) may be a hardy one in Zone 7. Generally, hardy bulbs can survive wintering in the ground without too much trouble, whereas tender bulbs have to be dug up and stored. Your local nursery can help you determine which bulbs are considered hardy in your area.

Shedding Light on Bulbs

A bulb is a structure that grows underground; it stores food during its dormancy and then supplies energy for an emerging plant. You know what bulbs are if you buy onions or garlic at the grocery. Good ones are dense and have some heft to them, plus a thin papery skin for protection; as bulbs age, their robustness diminishes and they dry out. They sometimes begin to sprout the beginnings of green leaves out of their tops. Gardeners also consider foods like potatoes, sweet potatoes, ginger, and water chestnuts to be bulbs. Garden bulbs are actually much the same as the ones at the grocery. Good ones have some plumpness and density because they’re full of healthy, moisture-filled plant tissue. They really are a package of life! With the right conditions, and in time, they’re sure to generate leaves — and the big payoff, gorgeous flowers.

A slick trick for keeping out moles and voles

If you’re having problems with moles (or other small animals), try using this formula to drive them out of your yard:

• 1⁄4 cup castor oil
• 2 tablespoons liquid detergent soap
• 6 tablespoons water Blend the castor oil and soap together in a blender (they won’t mix properly otherwise).

Add the water and blend again. Store this mix in a container till needed.
When you’re ready to apply the solution to the area where the moles are active, mix 2 tablespoons of the solution into 1 gallon of water. Pour it into the problem area (all over the affected area, not just down the holes).

Dealing with perennial pests and diseases

Good news — perennials aren’t especially pest-prone. If they’re growing in an appropriate spot with elbow room and you water regularly, they’re in good shape. And healthy plants are your best defense against potential problems. There are but a handful of common perennial-garden pests. Read on for their descriptions and some ways to control them:

• Aphids: These small whitish critters congregate on stems and nodes, sucking the life out of your plants. A strong spray from the hose can dislodge them. Ladybugs can also make a quick meal of aphids, so don’t get rid of these helpers.
• Black vine weevils (snout beetles): In late spring and early summer, these critters are harmless pupae resting in your soil. Then the adults emerge and eat the foliage of dozens of perennials (and lay eggs for the next generation while they’re at it). The telltale sign is notched leaf edges, especially lower down on the plant where the insects find more shelter. Starting in early fall, the newly hatched grubs eat roots. Launch your counterattack in fall by releasing beneficial nematodes (roundworms), available from well-stocked garden centers and mailorder sources; apply according to label directions. Other pesticides are registered for controlling these creatures; check with you local Cooperative Extension Service agent for more information.
• Leaf miners: These bugs form brown or tan or clear traceries — tunnels or channels — on affected leaves but rarely kill the plant. Just remove and discard affected leaves, and the plant will generate new ones.
• Root nematodes (roundworms): Affected plants develop severely distorted growth. Rip the plants out and discard them before the problem spreads.
• Voles: These little rodents slip out of their underground tunnels when you’re not looking and nibble on your perennials, especially the leaves but also roots, seeds, and bulbs. They’re a bit larger than mice, with a shorter tail and smaller ears. You can try trapping them with a baited mousetrap, but the best deterrent is a cat who’s a good hunter. Castor oil as a repellent works fairly well. You can also surround plants with small moats of sharp gravel.

As for diseases, they, too, are mercifully few on healthy perennials. You may encounter mildew or other fungal diseases. These problems appear as spots or a powdery coating on leaves, and severely affected plants may have distorted growth and buds that fail to open. If the problem is bad, tear out the plants or resort to spraying with a fungicide.
If fungal problems are chronic in your garden, your best line of defense is good air circulation, particularly in hot, humid summer weather. Also, be sure to pick off and discard sick leaves or clean up fallen affected leaves around the base of your plants. Regular, even watering right at the roots (that is, not splashing the leaves) is also wise.
Of course, an easy way to avoid both pests and diseases is not to grow vulnerable plants! You can deliberately seek out varieties touted as resistant.

Preparing perennials for winter

If you live in a cold are and want to overwinter your tender perennials, simply dig up the roots or entire plant and bring it indoors to a nonfreezing spot to spend a few months as a dormant or semi-dormant houseplant. Pot the plants in any good soil and grow them in a cool (40–50°F) and bright area. Keep them barely moist. The idea here is to just keep them alive until you can plant them back outside after the danger of frost next spring. Then with warmer temperatures and brighter light, they’ll spring back to life. You can also trim and prune down your perennials and use mulch to protect them through the winter.

Off with its head! Deadheading your plant

Deadheading is just a gardening term that refers to the practice of removing spent flowers or flower heads. Not only does it leave your perennials looking nicer, but it also encourages more blooms. Deadheading works by thwarting the plant’s natural inclination to go from flower to seed and thus finish up for the year. If you deadhead, the chemical messages that put that process in motion are stopped and the plant redirects its energies into making more buds and thus more flowers. You can keep a perennial in bloom a lot longer by doing this. So make a habit of deadheading your perennials every time you walk by. Toss the faded flowers on the compost pile. Or bring your clippers along and cut bouquets while the flowers are still in their prime — cutting fresh flowers has the same effect as later deadheading!