Mysteries: Laws of Nature and Gardening Revealed

Some of the mysteries of the universe reveal themselves in the garden. Why didn't my tulips come back? Did my husband deliberately mow down that rosebush? Here are answers to these and other pesky questions.

By: Linda Greider

My plant was labeled "perennial," but it didn't come back. What's up?

A little secret: There are long-lived perennials and there are short-lived perennials. While it's not uncommon to have decades-old stands of daylilies or peonies, which are among the longest-lived perennials, other plants may last only a season or two.

Among the short-lived: pinks, feverfew, geum, and hardy mums.

Long-lived perennials include some of the nicest: hellebore, gas plant, trillium, joe-pye weed, bee balm, astilbe, bugbane, and butterfly weed. All perennials will live longer if they're planted where they want to be: shade plants in shade, sun plants in sun, and all in good soil with lots of compost.

Ivy is growing up the trunks of my trees. Somebody told me it will choke the tree and kill it, but somebody else told me it's okay.

Mark Barbato, a licensed arborist with the Davey Tree Expert Company, says it won't choke the tree. Contrary to some old lore, the ivy doesn't live, vampire-like, off the tree.

But ivy will cause moisture to stay on the bark longer than it should, encouraging any fungus that may reside there to grow. Bark is meant to dry quickly after a rain, Barbato says.

To eliminate the ivy, don't yank it down but do cut it at the base and leave the vines to die on the tree. They'll soon wither, although their harmless tendrils may stay more or less forever.

Why don't deer eat daffodils? I know daffodils are poisonous, but how do the deer know?

Brent Heath of Brent and Becky's Bulbs in Gloucester, Virginia, says it's because every part of the daffodil from bulb to bloom tastes so bad. Just a teeny mouthful is enough to send critters fleeing.

It's unclear how the message gets passed on to young deer, but it does. Almost no animal eats daffodils. Heath notes that there are other nasty-tasting bulbs that get left alone, including anything in the amaryllis family--such as snowdrops, the beautiful foliage plant called arum, and a division of crocuses called Crocus tommasinianus.

Why does my dog dig up my lawn and garden? How can I stop him?

Nobody really knows the answer to either question, although many humans have made up answers. Some dogs dig and some dogs don't. I speak from 40 years of gardens-with-dogs experience.

What does "organic" mean when it comes to plants?

If you buy plants that are said to have been "raised organically," it means they've been grown from seeds or cuttings without chemical fertilizers or pesticides and that the grower has made every effort not to harm the environment. Organically produced seeds are now available, too, meaning they come from certified organically raised plants. You'll usually pay more for such products because they're costlier to produce.

When I go to a garden store to buy fertilizer, I see a bunch of numbers on the bag that seem important, but I don't know why. What do they mean?

Those numbers stand for phosphorous, nitrogen, and potassium, each of which affects a different aspect of plant growth.

Before getting tangled up in the details, consider that your garden probably doesn't need fertilizer at all. "There's no need to fertilize established plants that are doing well," says Mitch Baker, horticulturist at American Plant. This is especially true if you've used compost to enrich the soil and what you're talking about is trees, shrubs, or perennials.

Fertilizer might be better used on annuals that have to make a quick splash and on vegetable plants that need to produce quickly and generously.

If you do want to fertilize now and then, choose a "balanced" organic fertilizer that's relatively low in nutrients, Baker says. That means the numbers on the bag will be low and more or less the same--for example, 3-2-2. Organic fertilizer will be the least harmful to the environment.

For the record, the first number indicates the percentage of available nitrogen, the second phosphate, the third potash. In an ideal world, you would do a soil test to determine which of those your garden craves. Nitrogen helps plants produce top growth, or green growth, quickly. (Grass likes it, but too much on some flowering plants and you'll end up with a lot of lanky stems that don't bloom.) Phosphorous aids root systems and blossoming, and potassium has general protective effects.

How come my neighbor can grow banana plants all year and I can't? They're not supposed to be hardy here.

She's not a better gardener than you. She may simply have that most elusive thing in our area: sandy or loamy soil that drains exceptionally well. Winter wetness is death to all kinds of plants, and often a more important predictor than zone labels of how a marginally hardy plant will do in your garden.

Some plants that require excellent drainage: agastache, lavender, and gaura. Most others aren't so picky. The addition of compost, homemade or store-bought, to existing soil can improve drainage.

Brent Heath reports that even his dahlia tubers, planted in raised beds, have survived five winters so far. Normally they have to be taken out of the ground and stored over the winter if they're to revive to bloom another year. Raised beds naturally have good drainage.

If you want to compete with your neighbor, try raised beds or adding sand and compost by the ton to your existing beds.

Why didn't my tulips come back this year?

Like so many other plants we try to grow in the Washington area, your tulips wanted to be somewhere else. Tulips want to be on a dry Turkish steppe where they'll bake in the summer rather than stew as they do here, and they like well-draining soil all year round.

Some tulips are more perennial than others. Brent Heath recommends trying the class called Darwin hybrids or the smaller but equally gorgeous species tulips. Treat the others as annuals--at 50 cents or so a bulb, it's still a good investment.

The other reason your tulips might disappear is critters. Unlike daffodils, tulips are practically dripping sugar and therefore taste yummy. Deer will nip off the foliage then come back in a few weeks and get the blossoms. Digging or burrowing animals eat the bulbs.

Try planting the bulbs deeper than instructions on the bag indicate. A product called Plantskydd, available as a spray or a granular product that you spread around your planting beds, may discourage voles and rabbits and other small creatures.

As for deer, my own experience is that nothing keeps them away except a seven-foot-high fence.

I was weeding in my yard and something bit me. What could it have been?

If it's intensely itchy and you have small red welts here and there, especially in tight places such as your waistband, it was most likely a chigger. These teeny stealth creatures--actually arachnids, like spiders and ticks--bite you in the garden, but you start to feel the itch hours afterward as the little bugger squirts his saliva under your skin.

Chiggers stay with you only long enough to eat a little of your skin but don't burrow in and stay, as some old tales have it. Their itch, however, can last days or even weeks.

There's an assortment of other biting or stinging pests: mites, no-see-ums, ants, bees, centipedes, and wasps. Stings or bites from these creatures are usually obvious, and only in rare cases do they cause problems. Deer ticks are very small and not always noticeable, and any ring-shaped rash after such a bite should be reported to your doctor--it could be a sign of Lyme disease.

Then there are spiders. The two most venomous in our area are the brown recluse and the black widow. The black widow doesn't leave an obvious mark, and symptoms may not show up for minutes or hours. There may be pain in the area of the bite. In some cases, there might be muscle pain and/or spasms and a rise in heart rate and blood pressure. A gardener in our area made the science section of the New York Times last summer when he reported mysterious symptoms like these after gardening.

The bite of the brown recluse may not hurt until a few hours after. Nausea, vomiting, and eventually severe pain at the site of the bite may appear.

In both cases see a doctor, and next time wear long pants and socks when gardening.

Why do men and women differ--and sometimes argue--over the garden?

This may be the biggest gardening mystery of all. The answer? It's primal. And territorial.

In an informal survey of four married couples who occasionally garden together and two more who have learned not to, here's what I found:

• Men sometimes feel like nothing but laborers: They say their wives point at a spot in the yard and expect them to pick up a shovel and start digging.

• Women think men are disorderly. One woman calls her husband's planting style "orgy gardening" because to her eye he's planted everything on top of everything else.

• Men think women want to control them, so they control their lawns. They mow and seed and fertilize. Men can't hear women talking to them when they're mowing.

• Both sexes say the other can't admit defeat. One year, my husband threw annual seeds willy-nilly throughout my perennial borders. I was almost blind with rage. He didn't ask me--he just cast the seeds of hideous marigolds and other things.

The annuals came up and bloomed among the dignified perennials, a veritable riot of color. Everybody who saw the garden that year said it was the most beautiful they'd ever seen it. I still haven't forgiven him.