Dear Master Gardener: The snow has melted and there are still leaves on the lawn. Now that they have dried out should I chop them up with my mower and leave them on the grass or rake them up?

Answer: Mulching some leaves with your mower is the better option because the nutrients and organic matter will improve your lawn and soil. Mow over the leaves a few times to make sure they are ground up into small pieces. If you do this the leaves will not mat together, but will decompose into the turf adding valuable nutrients or micronutrients.

Otherwise, if you have a thick layer of leaves, rake them up or blow them off with a leaf blower. Leaving excessive leaf matter on your lawn going into winter can harm it by smothering the grass and inhibiting growth in the spring. In addition, it can promote snow mold diseases and damage from mice or voles.

Related: Ask the Master Gardener: Castor bean plants can be a dramatic addition to a garden

Dear Master Gardener: I didn’t get my dahlias dug up before it snowed. Is it too late?

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Answer: If you dig them up and they are mushy, they froze and it’s too late. If you dig them up and they are firm, clean them off, let them cure a day or two, then store them.

A Thanksgiving cactus. Photo by Jennifer Knutson
A Thanksgiving cactus. Photo by Jennifer Knutson

Dear Master Gardener: I purchased an orchid and the directions say to water it with an ice cube each week. Is this really a good way to water it?

Answer: Most houseplants originate in the tropics or subtropics and can be injured by icy water. Use room temperature water for all your houseplants, including orchids. As a general rule, an orchid in a 6-inch plastic pot is watered weekly. However, if it is hot and dry in your house and your plant is completely drying out in a few days or if you have it in a humid spot and it is staying damp, then you need to check the soil to see whether it actually needs to be watered. Water drainage is crucial for an orchid so it doesn’t get overwatered. It can be tricky to tell if an orchid has been over or under watered as the symptoms can look similar. If it is under watered the roots will dry and collapse, leading to shriveled buds and leaves that turn brown and drop. When an orchid is overwatered, the root system can rot and collapse and the buds will also shrivel and the leaves drop. In either case, you should change the watering schedule.

Orchids typically come double-potted. When I water mine, I remove the inner pot, take it to the sink, water it thoroughly with room temperature water, and allow the water to drain out for a few minutes. Make sure no water has collected on the leaves or in the crown, where the new leaves are emerging because this can rot new growth or create black rot spots on the leaves.

Related: Ask the Master Gardener: Prepare your garden for the coming winter

Dear Master Gardener: My Christmas cactus is blooming right now, but some of the buds have fallen off. What could cause that to happen?

Answer: Your cactus is probably a Thanksgiving cactus, since it is blooming now. There are three holiday cacti: Thanksgiving, Christmas, and Easter. They are in the same genus, but are different species and can be distinguished by the shape of their leaves. The Thanksgiving cactus has very pointed and claw-shaped projections on the edges of the leaves. The Christmas cactus has more scalloped or teardrop shaped leaf projections. The Easter cactus has rounded edges centralized on the leaf. They flower in response to the shortening of the days and cooler temperatures and bloom around the time of their holiday. The Thanksgiving and Christmas cactus may bloom again in spring, but probably won’t have as many blooms. They are all easy to grow as a houseplant and very long-lived. Keep them out of direct sunlight (near an east or west window is ideal) and in an area with cool nighttime temperatures. Fertilize them monthly June through August at half-strength and be careful not to overwater them. If your plant set flower buds and some have fallen off there could be several reasons: not enough or too much water, drafts or sudden changes in temperature, or it is receiving direct sunlight.

Related: Master Gardener: Protect your home from the wrath of woodpeckers

Dear Master Gardener: My handyman was helping me move my pencil cactus and pruned it because it was up to the ceiling and too tall to move. He ended up in the emergency room because his eyes were burning. Are they toxic?

Answer: The pencil cactus, also known as a milk bush, is native to Africa. It is not a true cactus, but a succulent. In nature it grows to about 30 feet tall, but indoors as a houseplant it grows 6-12 feet tall. It is in the Euphorbia family and like other Euphorbias it produces a toxic sap that causes severe rashes and eye irritation. When cut, this particular plant can ooze a lot of sap. It is essential to wear gloves when pruning a pencil cactus or any plant in the Euphorbia family. I am guessing your handyman did not wear gloves, got the sap on his hands, and rubbed near his eyes. With the Christmas holiday arriving soon, I will point out that the poinsettia is also in the Euphorbia family – the leaves and flowers are not toxic, but the stems have the milky sap that is irritating to the skin.

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.