This mystery vine should be considered toxic, assessing the risk of trees, and transplanting houseplants

A: The plant’s botanical name is Solanum dulcamara, which has several common names including red nightshade and bittersweet nightshade. In the same botanical family are edibles such as potato, tomato and eggplant, but also highly poisonous members such as deadly nightshade, Atropa belladonna.

As the old saying goes, one person’s wildflower is another person’s weed. Your plant, which we’ll call red nightshade, is listed on sites such as “Minnesota Wildflowers” as a weed, which can be defined as any plant growing where it’s not wanted, or has the potential to invade or harm its surroundings.

Red nightshade, and similar wild nightshades, develop large vining or shrubby structures and multiply rapidly by seeds contained in the red fruits. They can quickly overtake their surroundings, and although the purple flowers and red fruits are attractive, this nightshade might be considered a wolf in sheep’s clothing. Generally, the wild nightshades should also be considered toxic.

A reader’s dollar special vine purchased about five years ago from a home improvement store seems to be what is commonly known as red nightshade. Special to The Forum

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Q: I have a large silver maple tree in my backyard that looks pretty rough. The woodpeckers have also done a number on it, and I need input for cleaning it up or whether it should be cut down. Preferably I’d like to keep the tree, which is over 70 feet in height. — Bob M.

A: Another common name for silver maple (Acer saccharinum) is soft maple, which is a general indication of its lack of strong wood. The branch angles tend to be narrow and weak, and branch breakage is a common problem.

A common question of many owners of aging trees is whether the tree is “safe,” whether the tree is structurally sound, as well as the odds of the tree’s future lifespan. Unfortunately, these questions are complex.

Analyzing a tree’s condition or safety concerns is called tree risk assessment. Qualified tree risk assessors use their education, knowledge, training and experience to examine trees, and recommend measures to reduce the risk of living near trees. Completing a tree risk assessment may carry some level of liability, which is why it’s best to leave such assessment to those who have the appropriate training.

Only individuals who have earned the Tree Risk Assessment Qualification credential from the International Society of Arboriculture (ISA) have the training required for a thorough assessment. ISA-certified arborists are trained in tree care and can provide quality service for the homeowner. The nearest certified arborist can be found at https://www.treesaregood.org/findanarborist.

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Q: I’m new to houseplants, and I don’t know how often they should be transplanted into a larger pot. Is there a rule of thumb, such as once a year, for repotting? — Jenna H.

A: The need for repotting depends on how quickly the plant grows, and how quickly it fills the pot and soil with roots. An easy way to tell is to remove the plant from its pot by inverting the plant, giving a tap on the pot’s base and slipping the pot from the soil ball. It might be necessary to first run a knife between the pot’s inside edge and the soil.

With the pot removed, examine the soil ball. If the entire ball is tightly covered in circling roots, with little or no soil evident, the plant likely would benefit from repotting. Select a new pot only about 1 to 2 inches larger in diameter. Plants thrive best if the pot size is gradually increased as they grow.

Some plants can successfully remain in the same pot for decades, such as large, established Christmas cactuses. Fast-growing houseplants usually benefit from repotting every one to three years.

If you have a gardening or lawn care question, email Don Kinzler, NDSU Extension-Cass County, at donald.kinzler@ndsu.edu. Questions with broad appeal may be published, so please include your name, city and state for appropriate advice.