When a plant dies, the landscape looks bad. And so do you.
Maybe Mother Nature is to blame, or any one of a host of factors beyond your control. But dead plants are evidence of wasted time and money and affect your reputation. “Your clients are counting on you,” says Stacey Hirvela, horticulturist with . “When a plant dies, no matter what the reason, you appear less professional.”
The school of hard knocks teaches that you’re going to lose a plant occasionally, no matter how much TLC you give it. But learn from experience and avoid these common missteps to give every plant a fighting chance:
Plants have needs. Ignore what they want and they’re doomed. “Look at a site’s exposure, soil texture and moisture levels,” says Fred Kapp, education director for the , a green industry educational site, and program manager for the . “Then select a plant that fits those criteria. Plants have been adapting to certain conditions for millions of years. You can’t ignore genetics.”
Ditto for plant hardiness. “If a client says they want a plant but you know it’s not going to thrive in that zone, suggest an alternative,” says Kapp. Stick with natives or look for hybrids that are cold and heat tolerant and more resistant to disease and pests. And consider a plant’s mature size. Plants that are sized incorrectly require more maintenance, such as pruning, or eventual removal.
For shrubs, it’s generally fine to plant at the level of the container soil. But many container and balled and burlapped (B&B) trees have excess soil piled on top of the root ball. Remove the soil to expose the flare, the area where the trunk widens at the tree’s base. “The flare should be visible after you plant the tree, (either) at or slightly above grade,” says Kapp. “If the tree looks like a telephone pole, straight up and down, you’ve planted too deep.”
Make the hole the right size; dig two to three times wider than the root ball and only as deep as the root ball (you want the plant to sit on solid ground, not on loose soil that may settle). Look for circling (girdling) roots, which are common in container plants, and loosen and spread out as many as possible. Learn more techniques for handling roots .
It’s a misconception that burlap can stay in place because it decomposes. “That doesn’t happen quickly,” says Hirvela. “In the meantime, extra water is needed to saturate the material and get to the root ball.” Don’t just push the burlap down; cut away as much as possible once the plant is in the hole. Remove natural or synthetic twine so it doesn’t strangle the tree.
Cages should be cut off as much as is practical. Set the plant in the hole, snip around the cage on opposite sides at 12 and 6 o’clock and at 3 and 9 o’clock, then gently wriggle the pieces out. Even peat pots should be removed. “Your goal is to encourage fast and healthy root growth. Remove anything that gives the plant an obstacle to growing roots,” says Hirvela.
Everybody’s seen it: mulch piled up around the base of a plant to resemble a volcano. “A tree’s roots develop up high under the mulch and these roots eventually girdle and choke the tree,” says Nancy Buley, communications director with . “Piling mulch against the tree also keeps the stem moist and provides entry for disease and pests.” Mulch correctly: Add a maximum of 2-4 inches and keep it away from the plant’s stems.
Many B&B plants leave 75 percent or more of their roots in the nursery, so don’t let them dry out as they establish themselves. According to the , new trees and shrubs need about an inch of water through summer and fall or 2 inches in sandy soils. Small amounts of water two to three times per week are recommended over infrequent flooding, says Kapp. Your nursery, grower or extension service can provide advice on a watering plan.
Say it aloud: Topping trees is never OK. According to the , cutting off the top branches removes the leafy crown. Leaves make the food, so removing them forces multiple shoots to form below each cut. The new growth is weak and prone to breakage. A stressed tree also is more vulnerable to disease, insects and decay. If a tree needs to be reduced in size, consult an .
You may think you’re giving plants a head start by adding peat moss or bagged soil to the hole, but it’s not recommended. “A plant is better off acclimating to the soil it will grow in for the rest of its life,” says Hirvela. Furthermore, if you don’t mix in the amendment, you create a “bathtub effect” in which water enters the new material quickly but backs up and rots roots due to the different infiltration rate of the surrounding soil.
If amending, prepare a planting bed, not individual holes. Add compost, and till it into the entire area, mixing the backfill in thoroughly. Avoid using peat moss alone; if exposed, it can dry out and form a crust, causing water to roll off instead of reaching the root ball, says Hirvela.
Some plants like alkaline soils; some like acidic. Choose the wrong plant for the site and it struggles. “Get a lab soil test for an accurate analysis,” says Vanessa Gardner Nagel, owner of in Portland, Oregon and Vancouver. “Know what micronutrients are missing before you add anything.”
Haven’t heard about the boxwood blight but you just installed 50? Don’t know about rose rosette virus and yours are fading? Haven’t paid attention to impatiens downy mildew? Not educating yourself about new issues costs time, money, your reputation and the plants. Stay informed by reading TLC’s plant articles, attending extension classes and talking to nurseries.