Trumpet-shaped volunteer flower identified

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Q: What is this growing in my planter of dahlias? — Edye Nye, North Ferrisburgh, Vt.

A: What an interesting plant and flower. It's Nicandra physalodes, known simply as Nicandra or apple-of-Peru. It's considered a weedy member of the nightshade family, a weed being any plant out of place. Other members of this huge Solanaceae family include tomato, potato, pepper, husk-tomato and tomatillo, along with highly poisonous nightshades.

Nicandra's fruits are enclosed in a papery husk similar to the covering around ground cherries (aka husk tomato) that some gardeners grow as an edible. In checking the toxicity of Nicandra, I found conflicting reports, but it has anecdotally been linked to poisonings, so the fruit is considered inedible by humans. Birds are often the carrier of nightshade seeds, which explains why they pop up in unexpected places.

Q: I have a mature flowering shrub by my front door, and have been told it's called a Chinese Rose Tree or a double-flowering plum. We live far north by the Lake of the Woods and will be moving this fall. I'm wondering if I could dig up one of the shoots at the perimeter of the shrub and transplant. I wouldn't want to harm the mother bush in any way. Is this possible? — Nancy Peterson.

A: Your shrub goes by either name, Rose Tree of China or double-flowered plum, as you mentioned. The botanical name is Prunus triloba 'Multiplex.' If you can locate a small offshoot by the base, the offshoot can be dug with a spade. Sometimes it's necessary to separate the shoot from the mother plant using a pruning shears. The biggest challenge will be to get enough roots with the shoot. Usually you can find a branch arising near the base, but it's a little trickier getting it separated and dug with enough of a branched root system attached.

Although early spring before leaf-out is usually preferred for this operation, if that's not an option, fall is the next best season. Immediately wrap moist material around the roots for transport, or temporarily pot it up so the roots don't dry out. Depending on the height of the offshoot you're transplanting, it's best to cut it back by about one-half to compensate for root loss, which greatly improves success.

Q: My clematis hasn't been looking good all summer, what do you think the problem might be? — Lori Loff, Wahpeton, N.D.

A: When clematis vines lack vigor and leaves are more yellowed than rich green, it's usually the growing conditions, as clematis have few insect and disease pests. Clematis enjoy their face in the sun and their feet in the shade, as the old saying goes. A generous layer of mulch covering the root zone keeps roots cool and moist.

Clematis are also susceptible to yellowing from iron deficiency, especially in heavy clay soil and in alkaline deposits near concrete foundations. Apply chelated iron from garden centers and enrich the soil with organic material, like peat moss, bagged manure or compost. Clematis respond well to fertilizer added in May and June. Most varieties like the popular navy/purple Jackman thrive best if the top vines are left intact over winter, and cut back in early spring to about 6 inches above soil level before new growth begins from the base.