Dear Master Gardener: I would like a ground cover under a group of trees in my front yard. What do you recommend?

Answer: Since the area is under a group of trees you most likely need a shade-tolerant ground cover. Here are some good options:

  • Snow-on-the-mountain (also known as bishop’s weed) -- if you need a little plant to cover a large area, this is a vigorous groundcover that is great for filling shady spots. It has variegated green-and-white leaves with clusters of white flowers that bloom in summer. It tolerates poor soil and shade. Use it with caution -- it will spread aggressively!

  • Canadian wild ginger is a Minnesota native plant that has green, heart-shaped leaves and, if you look carefully, you will find a small flower near the ground in spring. Wild ginger tends to grow in colonies and spread by rhizomes. It makes a great ground cover for a shady area.

  • Lily-of-the-valley is slow to spread but long lived once established, forming dense colonies. It has green, oval-shaped leaves with fragrant, white, bell-shaped flowers that bloom in May or June. It gets 4-10 inches high.

  • Spotted deadnettle (Lamium) is a low (6-9 inches) spreading plant in the mint family. It is often used as a groundcover in shady areas and can cover large areas quickly. It is adaptable to a variety of light levels, so it is an excellent plant to use in transition areas between shade and sun. There are numerous spotted deadnettle cultivars with different leaf shape, size and variegation. It blooms prolifically in late spring and early summer then sporadically into fall. Flowers are either purple, pink, or white, depending on the cultivar.

  • Ajuga (bugleweed) grows best in part shade (at least 3-4 hours of sun per day). It will grow in full shade, but best foliage colors will occur in areas with part sun. It is a low-growing plant that spreads by stolons to form an attractive mat-like ground cover. It has purple flowers and blooms in early summer.

Dear Master Gardener: My husband thinks tomatoes, onions, and potatoes should be kept in the refrigerator and I think potatoes and onions should be stored in the pantry and tomatoes on the counter. Who’s right?

Answer: You win! Temperature and humidity are the primary storage factors that need to be considered.

  • Fresh, ripe tomatoes should not be stored in the refrigerator. They lose color, firmness, and flavor if refrigerated. Once they are cut, they should be refrigerated and will keep for about two to three days.

  • Onions should not be stored in the refrigerator. The cold temperature will soften their texture. Keep onions in a mesh bag in a cool, dry, well-ventilated place away from sunlight. The National Onion Association says not to store onions with potatoes or any other produce that releases moisture. Once an onion is cut it will keep for several days in a plastic bag or container in the refrigerator.

  • Potatoes should not be stored in the refrigerator. At temperatures below 45 degrees the starches in a potato begin to break down into sugars, which will cause the potato to darken when cooked. Store potatoes in a cool, dark, well-ventilated area away from light. When potatoes are exposed to light, they turn green and a toxic chemical called solanine will increase. Solanine levels are usually quite low, but you may want to discard potatoes that turn green because it gives them a bitter flavor.

Dear Master Gardener: My husband likes very hot peppers and would like me to grow some in my vegetable garden. Please tell us about growing hot peppers.

Answer: All peppers, whether bell, hot, or specialty, need warm weather, plenty of sunshine and water, and ample soil fertility. For the best success, wait until June to plant them in your garden. Choosing which hot peppers to grow can be fun -- imagine a pepper so hot that popping one in your mouth could send you to a hospital! There are some very hot peppers available! Some of the more commonly grown hot peppers include ancho, chili, poblano, habanero, jalapeño, and hot banana. Hot peppers get their heat from a compound called capsaicin. Capsaicin is in the seeds and the whitish membrane inside the fruit, so removing them before cooking or eating raw reduces the heat of the pepper.

The spiciness of hot peppers is measured in Scoville Heat Units (SHU), which indicates the amount of capsaicin present. Keep in mind that hot pepper flavor and Scoville heat units can vary by variety and growing conditions. The Scoville scale begins at zero with the bell pepper. Here are some SHU ratings for some of the more commonly grown hot peppers (the higher the number, the hotter the pepper): ancho and poblano 1,500-2,500; jalapeño 5,000; habanero range from 100,000 to 350,000; and a ghost pepper is about 1,000,000. The ghost pepper is the hottest pepper transplant you will find around here, but there is a hotter one – the Carolina Reaper reportedly has about a 2.2 million SHU rating! Capsaicin doesn’t dissolve in water so grabbing water to put out the fire in your mouth is useless. It will bind to the fat in milk, cheese, or sour cream. Capsaicin dissolves in alcohol -- beer doesn’t have a high enough alcohol content, but a straight shot of liquor might work!

Hot peppers can be picked at any color stage, but they are hottest when they are fully ripe. Mature color varies tremendously between varieties. Most hot peppers are firmly attached and should be removed with a knife or clippers to avoid damaging the plant. Take special care with hot peppers as some may burn bare skin when handled. And above all, don’t touch your eyes or sensitive body parts! Wear gloves when harvesting and handling, followed by a thorough hand-washing with soap and water to remove the capsaicin.

Dear Master Gardener: Are there any herbs I can grow that are perennial and will come back every year?

Answer: Chives are definitely perennial here. French tarragon and thyme are hardy to zone 4, but Crow Wing County Master Gardeners who are growing them in their gardens say they come back year after year.

You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at and I will answer you in the column if space allows.
University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.