Ask the Master Gardener: Adding ornamental grasses and more

Recommendations for grasses that do well in the lakes area, tips on annuals and perennials, restoring winter-killed grass and how to add a pop of chartreuse to a perennial bed are all part of this week's questions with the master gardeners.

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Korean feather reed grass (Calamagrostis brachytricha) is a warm season grass that is hardy to zone 4. Submitted photo

Dear Master Gardener: I would like to add a tall ornamental grass to my landscape. What do you recommend for this area?

Answer: Ornamental grasses are relatively trouble-free and grown for their varied foliage and unique flowers. Feather reed grass (Calamagrostis x acutiflora) is a cool season grass and a great vertical accent plant. The most popular cultivar is Karl Foerster, which reaches 1-1/2 to 2 feet tall and wide with 6-foot-tall bloom stalks. This grass flowers in early summer. For best results, plant it in full sun and keep the soil evenly moist. Korean feather reed grass (Calamagrostis brachytricha) is a warm season grass that is hardy to zone 4, but has been successfully growing in my garden for several years. The flowers open in the fall. The height of this grass with the bloom is 4 feet. It also grows best in full sun, but will tolerate part sun. An underutilized ornamental grass is the silver spike grass (Spodiopogon sibiricus). It is a warm season grass that should be planted in full sun to attain the beautiful golden-orange or burgundy-red fall color. It reaches 5 feet with the bloom stalk and must receive adequate moisture.

Dear Master Gardener: Are sweet peas perennial or annual? Is it too early to plant them?

Answer: Sweet peas are very popular in English gardens. There are both perennial and annual varieties. Perennial sweet peas are Lathyrus latifolius and are hardy to zone 4. Annual sweet peas are Lathyrus odoratus and are very fragrant, unlike the perennial varieties. It is not too early to plant seeds; in fact, they should be planted in very early spring as soon as the soil is workable. They are cool season plants and perform best in cool weather. The vining type of sweet peas need a trellis to support them as they grow. Plant the seeds 3/4 to one-inch deep, 2 inches apart, in full to part sun. Germination may be quicker if the seeds are soaked for 24 hours before sowing. Thin them 5 to 6 inches apart โ€“ they need good air circulation. When the seedlings are about 4 inches tall, pinch off the tip of the stem above the top set of leaves, which will create a bushier plant with more branching. Sweet peas are wonderful as a cut flower and have a vase life of about five days.

Dear Master Gardener: Can we grow holly in this area?


Answer: Yes, winterberry (Ilex verticillata) is a deciduous holly, native to Minnesota. It has female flowers and male flowers which occur on separate plants. Fruit will only be produced when both a male and female plant are planted near each other (up to 40-50 feet). One male plant produces enough pollen to pollinate many female plants. When purchasing winterberry read the plant tags to make sure you have compatible male and female plants. Winterberry provides seasonal interest in autumn and early winter when female plants are covered in red, orange, or yellow fruit clustered tightly around stems. The fruit attracts many songbird species.

Dear Master Gardener: When my tulips and daffodils are done blooming should I cut them down to the ground?

Answer: When tulips and daffodils are done blooming, cut off the spent blooms only. The leaves and stems are needed for photosynthesis to put energy into forming new bulbs, so leave them until they turn brown and dry up in early summer.

Dear Master Gardener: One of my larger perennials didnโ€™t make it through the winter and now I would like to add a pop of chartreuse to my perennial bed. Is there an easy perennial that fits the bill?

Answer: Yes! Aralia โ€˜Sun Kingโ€™ is one of my favorite perennials and hardy to zone 3. I have them in gardens ranging from full shade to full sun. The color will be brighter yellow in part sun and more chartreuse or lime green in full shade. Tiny white flowers bloom mid to late summer followed by inedible, purple-black berries. It reaches a mature height and width of 3 feet by 3 feet.

Dear Master Gardener: Will lavender grow in the Brainerd lakes area?

Answer: Most lavenders (Lavandula) are hardy in zones 5-9; unfortunately, they are not hardy here in the Brainerd lakes area, which is zone 3b. Lavender will need to be grown as an annual outdoors, or can be potted up in the fall and with luck, overwintered indoors.

Dear Master Gardener: There is dead grass on both sides of our sidewalk and along parts of our driveway. What should we do?


Answer: Those locations probably indicate too much salt was applied this winter. Dead spots in the lawn can also be caused by snow mold and pet urine. Rake out as much dead grass as possible. Then flush the dead area deeply with a hose several times to neutralize the concentrated contaminants. Scratch the surface of the soil and overseed with grass seed appropriate for your lawn. Keep moist until grass germinates and establishes. Next year, treat icy patches with clay kitty litter or coarse sand and keep the salt out of the grass and our waterways.

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.
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