Dear Master Gardener: I have a lot of trouble with squirrels digging in my containers of flowers and flower beds. What is the best remedy for this, other than eliminating squirrels?

Answer: Those pesky squirrels can be a very frustrating problem! They dig in containers to bury their stash of acorns and nuts, dig up newly planted bulbs in the fall, strip bark off trees, steal bird seed from bird feeders scaring off the lovely songbirds, and dig up flower beds. Some experts suggest placing stones or river rock on top of the soil in containers, or placing chicken wire on top of the container before planting then cutting holes in it for the plants.

If you have bird feeders, you could place them far from your gardens or stop filling them with birdseed, especially sunflower seeds which attract squirrels. Or, purchase squirrel-proof feeders.

Related: Ask the Master Gardener: It’s not too early to plant climbing roses Agriculture Canada, and more recently the University of Minnesota, have developed many hardy roses for northern climates.
Squirrels dig up flower beds, burying nuts to dig up later. Jackie Burkey says they dug up everything in her gardens burying black walnuts last fall and are now digging everywhere trying to find them. She put chicken wire over the Muscari she planted last fall, which is a technique recommended by the University of Minnesota to protect newly planted bulbs. It’s probably the most effective in the fall when the squirrels are busy stashing away their food. I regret not doing it last year because the squirrels dug up all the lily bulbs in a large area of my perennial garden, which had been there for years unscathed. I have found peanut shells buried in my garden, which is baffling since I haven’t bought peanuts in the shell. Both Jackie and I have sprinkled Milorganite around our plants, which seems to slow them down and deter them a little. Milorganite, which is also a mild fertilizer, has worked for me at deterring rabbits and deer also, although I double up and spray plants, too. Some experts, including Professor Jeff Gillman who conducts experiments about garden myths, say that repellents can be effective, although no repellent will ever be perfect. Professor Gillman states that the most common constituents of homemade mammal-repelling sprays are garlic, hot peppers, and rotten eggs. Other natural repellents that have had some success are peppermint, catnip, and hot pepper sauce. He says, “Extracts from these plants and plant products were effective at repelling deer, rabbits, and squirrels to one degree or another.” (“The Truth About Garden Remedies,” p. 155). Another suggestion from a Master Gardener is to sprinkle cayenne pepper or blood meal on the soil to deter them — both in containers and gardens. I hope at least one of these ideas works for you!

Related: Ask the Master Gardener: Protecting your plants from spring frost If snow and freezing temperatures are in the forecast and going to persist for a few days, it would be a good idea to protect new and recently sprouted plants with a cover or keep them potted so you can move them to shelter.
Dear Master Gardener: I would like to grow strawberries, but we don’t have space in our yard for a garden. Can I grow them in pots on our deck?

Answer: Strawberries do well when grown in pots, planters or hanging baskets as long as you choose the right kind. There are two types of strawberries: day-neutral (also called everbearing) and June-bearing. You will want to purchase day-neutral strawberries for containers. Day-neutral strawberries are usually grown as annuals. Good varieties include Albion, Evie-II, Portola, San Andreas and Seascape. If you plant the strawberries in full sun (at least eight hours) in a well-draining potting mix meant for containers and keep them well-watered, you can expect to get one-half to 1 pound of fruit from each plant from July through the first frost. Place the plants about 8 inches apart. If you are planting them in a long rectangular planter, you can plant them 6 inches apart in a staggered row. If you are growing them in 12-inch hanging baskets, put in three plants. Because they can be planted relatively close together, you can get a lot of fruit from a small space.

Related: Ask the Master Gardener: Reinvigorating your roses Don’t panic yet if you find black stems on rose bushes. Just cut them back and lightly fertilize as soon as the leaf buds start to open.

May Gardening Tips

• There is no need to test your garden soil annually, however if plants have been growing poorly the past few years even with proper care, you may want to get it tested. Visit the U of M Soil Testing Lab website at: http://soiltest.cfans.umn.edu/ to download a questionnaire along with instructions on taking and sending in samples. If the problem is due to a nutrient deficiency or excess alkalinity or acidity, they will suggest a remedy depending on what you are growing. A regular garden soil test costs $17.

• Early May is a good time to plant grass seed. For good results rough up the soil first.

• In most years, mid-May is a good time for applying pre-emergent crabgrass killer before crabgrass seeds start to germinate and seedlings poke through the soil surface.

• Peas, leaf lettuce, spinach, and radish seeds can be planted the first or second week of May. Transplant onions and members of the cabbage family (cabbage, cauliflower, broccoli) while soils are still cool. Sow seeds for beans, beets, carrots, turnips, and sweet corn when all danger of frost has passed and the soil is workable. Wait until after Memorial Day to plant tomatoes, peppers and eggplants.

• Plant perennials any time after mid-month. Nectar-producing plants for butterflies and other pollinators include: Asclepias (milkweed, butterfly weed), Echinacea (coneflowers), Joe Pye Weed, Monarda (bee balm), Nepeta (catmint), and Anise Hyssop.

• Consider registering your butterfly garden as a monarch waystation. For more information visit http://www.monarchwatch.org/waystations/index.html

• Acclimate (harden off) seedlings by moving them outside into a protected area two weeks before the last frost date. Expose them to a little more sun every day. Bring them indoors if frost is forecasted.

• Wait until you are certain there will be no more frost before adding annuals to the garden. Most annuals, especially impatiens and geraniums, have no frost tolerance. Pansies, violas, and johnny jump-ups will not be killed or badly damaged by frost. Calendulas, snapdragons, and sweet alyssum may also be planted a little early.

• Annuals that grow easily and quickly when you seed them directly into the garden include zinnias, cosmos, bachelor’s buttons, four o’clocks, California poppies, Bells of Ireland, and marigolds.

• Be on the lookout for pine needle scale crawlers later in the month. Mugo and Scotch pines are most at risk, but other pines and spruce are frequently attacked. Eggs of the first-generation hatch in May (around the time common lilacs are blooming). Look for white scale covers and lift the covers to see if eggs are present. Look for active reddish crawlers. A hand lens is helpful to look for eggs and crawlers. Insecticidal soap or horticultural oil is a spray treatment for the crawler stage. Combining a crawler spray with a systemic treatment is the most effective. Prune and destroy heavily infested branches.

• If you have an ornamental crabapple tree that is prone to apple scab (leaves that develop dark spots, then drop) begin a fungicide spray program before its flower buds open. If scab is bad every year, you may want to replace it with a scab-resistant variety such as Red Jewell or Coralburst.

Related: Ask the Master Gardener: Lilies add beauty and fragrance to any garden Many gardeners in the Brainerd area plant Oriental lily bulbs in the spring and treat them as annuals and/or enjoy them as cut flowers.

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 umnmastergardener@gmail.com 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.