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Gardening mistakes to avoid

Garden writers try to help gardeners skip their own worst blunders, just as friends don’t let friends repeat familiar mistakes. I know you will save time, money, embarrassment and dead plants by avoiding these most common errors and doing things the right way.

1. Watering wrong

Recently my perennials class laughed when I said, “Watering: The way new gardeners kill plants.” Some gardeners water too much and drown plants. But more commonly people water too little, even though they staunchly declare “I watered every day!” Picture the gardener, waving the water wand around until the top of the soil is darkened with moisture: She thinks she watered.

The right way: Direct water at the base of the plant until the plant’s root ball is thoroughly moistened, whether it’s a 4-inch annual or 12-inch tree root ball. Water deeply whenever the top inch of soil feels dry – but not daily (except in the case of tiny seedlings or some container plants in severe drought).

2. Hole too small

Uninformed or lazy helpers sometimes dig holes just a little bigger than the root ball, and pop in the tree, shrub or perennial. That’s wrong. Odds are the new plant will never push its roots outward through that hard wall, and it will drown in its little clay basin.

The right way: Dig a hole at least three times as wide as the plant pot or root ball. Make it only as deep as the pot (because you don’t want the plant to settle down into a hole). Take the plant out of the pot and place it in the hole, making sure that the level of the plant remains a tiny bit higher than the soil level. Do not rip apart the roots, unless they are tangled and circling. (In that case separate them gently and direct them outward.) Fill in the hole with your own excellent topsoil or a mixture of compost and topsoil.

3. Failure to weed early

To paraphrase Ben Franklin: A goutweed caught in time saves nine – or rather, 99 of the dastardly thugs. If you see a couple of goutweeds, creeping Charlies, horsetails, bugleweeds, cinquefoils, creeping speedwells, or – name your enemy – drop everything you are doing and get rid of them now. Weeds, by definition, are opportunists. They quickly take advantage and multiply prolifically.

The right way: Weed early in the season, and quickly when a new weed appears. If you find a new weed, dig out the entire area around it. Cover that area – at least a foot in all directions – with an opaque tarp, cardboard, thick newspaper or heavy black plastic. Watch for any new emerging weeds that pop up from seeds or pieces of root left in the soil.

4. Over mulching

Mulch is good – blocks weeds, holds in soil moisture and slowly decomposes, adding organic matter to the soil. But too much is too much. Sometimes a landscaper or homeowner spreads 2 or 3 inches of shredded bark mulch over the soil around shrubs and trees, and then every year somebody adds more. Rain can’t get through it to the plant roots, and nothing down there can breathe. Even worse, somebody once mounded mulch high up a tree trunk and somebody else liked it– and “volcano mulching” was born. It is bad, wrong, and destructive. Mulch against tree trunks will rot the trunks.

The right way: First, you do not have to mulch at all. In England gardeners commonly leave bare soil between plants and use a hoe to “cultivate” the surface to knock off weed seedlings. If you do use mulch, don’t let it pile up deeper than 2 or 3 inches. At the end of winter you might rake back the old stuff, add a little compost around the plants, and respread the mulch, adding just a little if needed. When spreading mulch around perennials or woody plants, keep the mulch off the plants and away from the crowns or trunks. Also remember that woody mulch is for use on top of the soil – not to be turned in. (To improve soil texture and nutrition, turn in compost.)

5. Overcrowding

Two mistakes happen all too often: The home gardener buys beautiful looking plants and arranges them artfully in the space available. He places them according to their looks now, rather than believing the spacing indicated on the tag. Plant tags usually show height and width or spread. Similarly a landscaper might lay out a new bed with small shrubs – that look great the first year but will be severely overplanted and overcrowded within just a couple of years. (Some CNLPs have told me how often they have recommended appropriate spacing, knowing the future size of the shrubs, but the homeowner has insisted on more plants because it looks so sparse!) Many plants are also placed where they will soon be too tall for the site because nobody heeded the “height at maturity” listed.

The right way: Read and believe the mature height and width of the plants you are considering and place them where they will look great in three, five or 10 years. If the design looks sparse, fill in with annuals or container plants during the first years.

6. Beds too small

Does a big guy love sleeping in a twin bed? Does a 12-by 6-foot rose of Sharon fit in a 2-foot wide landscape bed? Certainly not. Yet I see this everywhere: Narrow (2 to 4-foot) “foundation beds” tucked close against the base of houses. Then they are crammed with junipers, lilacs and rhododendrons that will never get enough sun, water, or space to become the plants they’re meant to be.

The right way: Leave space around the foundation for access to the structure. Then prepare a planting bed at least 6 feet wide so you’ll have room for great plants. (One guideline: The bed around the house looks proportionate if it’s one-third the height of the house.)

Do these things right in the first place this season – and then go make your own new mistakes. I know I will.

Sally Cunningham is a garden writer, lecturer and consultant.