DEAR JESSICA: Do you know what this green mottled, red-stemmed vine is? Is it a type of poison ivy?
— Loretta Sehlmeyer,
DEAR LORETTA: That’s variegated Ampelopsis brevipedunculata, very likely the ‘elegans’ cultivar. It’s very invasive but nevertheless is still sold in some nurseries and garden catalogs as an ornamental, so some folks are planting it deliberately. Unless you’re prepared to pull up and contain it continuously, I suggest you remove it; the Asian native is on the New York State Prohibited and Regulated Invasive Species list.
Also known as porcelainberry, the vine is “a vigorous invader of open and wooded habitats where it shades out native shrubs and young trees. As it spreads, it climbs over and blankets existing plants and weakens and kills them by blocking sunlight,” according to the U.S. National Park Service.
To eliminate it, remove vines while they’re young, as established ones develop a strong root system that may be very difficult to remove. If it’s too late for that, cut stems or leaves to provide a point of entry and apply a systemic herbicide like glyphosate or triclopyr to kill entire plants, including roots — taking care to protect nearby plants because the chemicals will kill whatever it contacts in the garden.
DEAR JESSICA: I will be bringing a Stellar geranium in the house for the winter. What should I do to make sure I do not bring in any pests that may destroy my other houseplants?
— Diana White,
DEAR DIANA: I get the impression you are planning to treat your geranium as a houseplant over winter, but you should know it likely will grow leggy and sickly, as geraniums require more sunlight than your brightest window can provide during winter. There is a better way to overwinter geraniums, which I’ll describe below, but if you really want to try to keep it growing, the trick to keeping pests from hitching a ride on them is to rinse them well and change the soil.
First, however, you should help acclimate the plant to its new location by setting it in the shade for a week or so before moving it indoors. Then, carefully remove the plant from its pot and gently brush off as much soil from the roots as possible, and wash the container with a 10 percent bleach solution and rinse. (If the plant had been growing in the garden, you won’t be able to acclimate it and should just dig it up and proceed with the step below.)
Rinse the plant — roots and all — briefly in cool water, and replant it immediately in a clean pot with fresh potting mix (not garden soil).
Again, this isn’t your best option, but that answers the question you asked. Instead, I recommend digging the plant up before the first frost, shaking the loose soil off its roots and placing the entire plant into a paper bag. Take it out once a month over the winter and soak the roots in water for an hour or two, then return it to its bag.
In late March, cut the plant back, removing any dead or limp stems, and pot it up. Place it by a sunny window and resume watering until May, when you can bring it back outdoors.
DEAR JESSICA: My potted tomato plant is growing nicely, but the tomatoes are not. As you can see, they are rotting from their bottoms. The plant is in a large plastic container with one small drain hole on the bottom. It’s growing in potting soil, and I don’t use any fertilizer. What can I do to get the plant healthy? What is causing this to happen?
— Sam Realmuto,
DEAR SAM: That’s blossom end rot, which is caused mostly by uneven watering, which results in a calcium deficiency. My guess is the one small drainage hole in your pot could be at least partially responsible, as are your watering practices.
You can’t save the affected tomatoes, but you can save your plant and ensure the health of future tomatoes by drenching leaves with a liquid calcium spray, such as Enz-Rot. Afterward, ensure you water consistently — the same amount each time you water. You may need to water as often as twice daily on the hottest, sunniest days, as containers tend to dry out quickly.
Tomatoes also are heavy feeders, so in addition to poking more holes to allow for better drainage from the bottom of the pot, you should be fertilizing your plant.
In general, container-grown plants need more water than those growing in the garden. That’s because in the garden, roots can spread out in search of water if the soil right around them becomes dry. That luxury isn’t available to container-grown plants; the only water available is in the container with them, and when it’s gone, they’re out of luck unless you provide more. Similarly, the only nutrients available to a potted plant are those in the original potting mix. And when those are used up, more need to be added to keep the plant healthy.
In addition to other nutrients and minerals that may be present in fertilizer, the main components are nitrogen, phosphorus and potassium, represented by a three-number ratio on package labels. Nitrogen aides green, leafy growth; phosphorus helps with fruiting and flowering, which is most valued when growing tomatoes; potassium works on the overall health of the plant. Look for a product that either lists three identical numbers in its ratio (5-5-5 or 10-10-10) or one that contains a higher ratio of phosphorus (5-10-5 or 10-20-10,) and apply according to package directions.