health

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What’s Wrong

With My Plant?

(And How Do I Fix It?)

This handy book helps you diagnose problems and keep your plants healthy!

problem solver

Crown vetch

Coronilla varia

IDENTIFICATION — Crown vetch grows up to 2 ft. tall. It has a dense, sprawling habit with stems that can be 5 to 6 ft. long. Pink flowers are followed by 3-in.-long seed pods. Although it’s still being sold and planted, you do not want this near your garden. It can spread quickly with seeds, root and stem pieces, and it’s tough to get rid of.

FAVORITE CONDITIONS — You’ll find this pest in full sun to part shade in rocky or rich soil. Once used to control erosion along roadways, this weed escaped and is forcing out native plants.

CONTROL — Dig crown vetch out of established gardens or use a selective herbicide in turf areas. It’s a perennial, so for the best control, apply herbicide in fall, before the leaves go dormant, and again in spring as the leaves emerge. Repeated mowing also keeps this weeds from producing seeds.

When you’re tackling crown vetch and other weeds with tough roots, a good weeding tool, such as our Soil Knife, really comes in handy.

Click for a foliage detail.

problem solver

Box elder

Acer negundo

IDENTIFICATION — Box elder leaves have three lobed leaflets that are somewhat pointed. The stems are smooth green to dark red with a white waxy coating that you can rub off with your fingers. Click to see a foliage detail.

A single or multi-stemmed tree that grows up to 75-ft.-tall, box elder is not good to have in your garden. Winged seeds can sprout almost anywhere and new trees can also sprout from the shallow roots, which make it hard to grow anything nearby. In addition, its weak wood breaks easily in storms.

FAVORITE CONDITIONS — Box elder is not picky. Any place in full sun to part shade with moist, even wet soil is fine. It readily adapts to almost any conditions except deep shade or very dry soil.

CONTROL — Pull seedlings if you spot them when they’re young enough. This is the best method in areas where you can’t dig or spray, such as in ground cover beds.

Spray young sprouts in open, mulched areas with nonselective herbicides, such as Roundup^® Poison Ivy & Tough Brush Killer Plus. Always follow the label directions, but you usually apply these products to actively growing weeds in spring or summer.

Digging is the preferred method in beds where spraying a herbicide would be risky for the other plants. Plus, unlike spraying actively growing weeds, digging lets you get rid of box elder any time you can push the shovel into the soil.

Once box elder gets too big to dig, you’ll need to use a saw to remove it. Then dribble or brush on a systemic stump killer around the edges where the sap is flowing. It’s absorbed into the wood and kills the roots.

tree pruning tools

Whether you’re new to tree pruning or have been doing it for years, you’ll find that one of the best times to start is when plants are dormant in winter or early spring. You can see the branches that need to be removed without all of those leaves in the way. And it’s good for the tree, too: The rising sap in spring will stimulate new growth to make the wounds heal over faster.

With a couple of exceptions, you can prune almost any deciduous tree this time of year. Maples and birches bleed sap if their bark is injured in the spring. Losing sap won’t kill the tree, but it is messy as it runs down the trunk or drips from branches. It’s better to wait until midsummer to prune these two trees.

Here are a few problems to watch for: Water sprouts are shoots that grow strictly upright from along the main branches. Stubs are blunt-ended branches left on the tree that detract from its natural or graceful shape. Crossed or rubbing branches create opportunities for disease or pests to enter. And finally, high up in the tree, too many small branches block sunlight, so the tree might need a little thinning. Once you’ve spotted some of these problems in your tree, the next step is to gather the right pruning tools.

HANDHELD PRUNERS — Carry your pruners with you whenever you’re in the garden so you can snip small water sprouts, suckers and twigs as you spot them. Most pruners will cut branches with a 3/4-in. diameter with no problem. Some prefer bypass or scissor-cut pruners like these because they cut close to a branch and won’t leave a stub. Unlike anvil pruners, they’re less likely to crush the bark at the edge of the wound.

These Felco pruners are our favorite — buy our Pruning Gift Set, which includes a #2 or #6 pair of Felco pruners, a sheath and The Pruner’s Bible, and we’ll throw in a free sharpener.

PRUNING SAW — If you’re removing branches smaller than 3 in. in diameter, a pruning saw works fine. The curved blade allows you to get into tight places. Or try a double-edged pruning saw. One edge has coarse teeth for rough cutting and the other has smaller teeth for making finer finish cuts.

POLE SAW — With this tool, you won’t need to climb into the tree or drag a ladder out of the shed to reach branches 15 ft. up. This pole saw has a curved blade so you can hook onto and easily cut a 2-in.-diameter branch. On the opposite side of the saw is a hook with a lopper blade that cuts when you pull on a rope. It comes in handy when you’re snipping small branches or twigs as you thin the crown.

problem solver

Eastern cottontail

Sylvilagus spp.

IDENTIFICATION — Most of us know a rabbit when we see it — long ears, fuzzy tail and a piece of your favorite plant dangling from its mouth! Eastern cottontails, the most common, are found across North America.

DAMAGE — These pests do eat annuals and perennials, but the damage is usually cosmetic, although they can ruin a vegetable garden or your favorite spring bulbs. But worse yet, they can girdle and kill shrubs and small trees, often the most expensive plants in a garden. Damage to trees is more severe during the winter when there aren’t green plants for rabbits to munch. If you look closely at the trunk, you’ll see characteristic small, paired tooth marks. The damage usually starts a couple of inches from the ground and goes above the highest snow line.

CONTROL — First, make the area less attractive by removing hiding places like brush piles. There are hundreds of home recipes for keeping rabbits away. Some people swear by them; others may find that they simply don’t work. In any case, they probably won’t keep really hungry rabbits at bay for long.

Chemical repellents, like Ro-Pel^®, are effective, but most of them need to be reapplied after rain and several times during the winter. A cylinder of 1/4-in. hardware cloth will keep rabbits away from shrubs and young trees. The bottom of the cylinder needs to be 3 in. below the soil’s surface to prevent digging, and the top needs to be 24 in. above the anticipated snow line. Or you can use rigid plastic tree guards, although in extreme cases, rabbits can chew through them.

You can fence off an entire bed with chicken wire or hardware cloth, but make sure there are no rabbits hiding inside when you’re fencing. Check the bed periodically during the winter to make sure that no rabbits have managed to move in.

problem solver

American elder

Sambucus canadensis

IDENTIFICATION — A quick way to identify this tree seedling is to crush a stem or a few leaves and you’ll get a disagreeable odor. Break or cut a mature stem and you’ll discover a spongy white pith in the center. And last but not least, the creamy white flowers in spring and the dark purple fruits that follow are in large, flat-topped clusters.

FAVORITE CONDITIONS — Full sun to part shade in moist, fertile soil is where you’re likely to find American elder. It also tolerates moderately dry conditions.

CONTROL — Pull or dig out saplings or spray with a nonselective herbicide like Roundup^®.

PHOTO: © Joseph G. Strauch, Jr.

problem solver

Cedar-apple rust

IDENTIFICATION — In fall, you’ll spot hard brown galls on twigs of Eastern red cedar. In spring the galls swell, turn orange, as in the photo, and release spores.

DAMAGE — When those spores find the foliage of an apple tree in late spring, spots of orange rust, like the ones in the small photo, grow on the leaves during the summer. Infected leaves drop off in midsummer, leaving the tree unsightly. As they ripen, spores from the apple are then blown back to the cedar to continue the cycle next year.

CONTROL — Grow rust-resistant apple cultivars and don’t plant Eastern red cedars and apple trees in the same garden. If you have susceptible apple trees, spray them with a fungicide as a preventative when the flower buds begin to open in spring.

PHOTO: © Jerry Pavia

problem solver

Chameleon plant

Houttuynia cordata

IDENTIFICATION — Often sold as an ornamental, the leaves of chameleon plant are green with margins of red, bronze or yellow and have a pungent odor when they’re crushed. The plant reaches 6 to 12 in. tall and spreads by underground rhizomes, rooting stems and seeds.

FAVORITE CONDITIONS — It prefers wet soil in sun or shade; in dry shade situations it spreads much slower.

CONTROL — Start digging and keep digging or spray with a nonselective herbicide. If you want to keep some, plant it in a buried container so the roots can’t run.

problem solver

Musk thistle

Curduus nutans

IDENTIFICATION — All the surfaces of the leaves and stems of musk thistle are covered with sharp prickles. The spiny multi-branched stems reach 2 to 6 ft. tall. From summer to fall, its showy red-purple flowers open, the flower heads drooping as they age.

FAVORITE CONDITIONS — The seeds of this biennial weed sprout in summer, in full sun or shade, in areas not regularly cultivated, such as fence rows, garden perimeters and lawns.

CONTROL — Sharp spines make hand-pulling this weed difficult. So hoe the young plants or spray a broadleaf herbicide before the seeds ripen.