“Ask the Plant and Pest Professor” is based on questions received and answered by the Home and Garden Information Center (HGIC), an educational outreach program of the University of Maryland Extension. Please visit our website for gardening, pest management information or to send us a question by clicking ‘Ask Maryland’s Gardening Experts’. Follow us on Facebook, Instagram and Twitter.
Question #1: Which of the following herbs are hardy enough to survive being planted outdoors in Maryland winters: parsley, garlic, chives, lovage, oregano, fennel, marjoram, rosemary, sage and thyme?
Answer #1: Under most normal winters, all of the herbs mentioned will survive. But our winters are very variable so in some years winter protection would be advisable. A layer of mulch placed around plants after the ground is frozen helps to protect the roots from the freezing and thawing of soil. After the danger of frost has past rake the mulch away from the crown of the plants. Plant your herbs in a protected location to shield them from drying winter winds. Rosemary can be winterkilled and could benefit from a temporary burlap windbreak. A screen can be easily constructed by wrapping burlap around garden stakes. Garlic is planted in the fall. The bulbs are harvested in early July so replanting each season is necessary.
Question #2: We just planted a young holly tree in November. What should we do for it this winter? Should we water it? We are afraid that if we do water it now the soil will freeze and the roots will die.
Answer #2: You do not need to do anything for your tree now but hopefully you watered it well after you planted it. Water evaporates from soil very slowly in the winter, so it stays moist for a long time. We have had plenty of rain this winter. Moist (not soggy) soil is crucial for the success of new plantings. Keep an eye on the weather for droughty periods, which typically occur in summer going into the fall. Water the tree deeply when we do not get regular rain for at least the first two years. A 2-3 inch layer of mulch (not touching the trunk) will also help to keep the soil moist.
Question #3: In October I planted some tulips, daffodils and hyacinth in my front garden bed. I noticed that the leaves of the daffodils are already sprouting. Isn’t this too early? Will the bulbs be damaged and is there something I should be doing to protect them?
Answer #3: Bulb growth will stop with colder temperatures. The foliage may sustain winter damage but that will not affect the spring bloom. Covering them is not absolutely necessary. But if you choose to do so, lightly cover (do not bury them) with mulch, shredded leaves, evergreen branches or pine needles. Uncover in early spring.
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