5 days Ago By Jennifer Knutson | U of M Extension Master Gardener
Dear Master Gardener : I like to make dried floral arrangements and was wondering if there is an ornamental grass that I can plant for that purpose? Answer : Northern sea oats (Chasmanthium latifolium) is an ornamental grass that looks lovely in the garden for at least half the year. Its seed heads hold up well into the winter, adding winter interest to the garden. This cool season grass is hardy to zone 3 and is a host plant to several woodland butterflies.
Northern sea oats reach 2-3 feet in height with a spread of 1-2.5 feet. It grows in full sun to part shade, preferring light shade, and is one of the more shade-tolerant of the ornamental grasses.
Be aware that if you grow it in rich, fertile soil, it may readily self-sow and spread aggressively. It would probably be best suited to use as a tall groundcover in an area where you don’t mind if it spreads into a large mass, rather than encroaching on your prized perennials. The seed heads start out green then turn purplish bronze by late summer.
They are very showy and are excellent for dried floral bouquets and arrangements. ADVERTISEMENT Dear Master Gardener : I brought my potted rosemary plant in for the winter. How do I take care of it and how do I trim it? Answer : According to the University of Illinois Extension, rosemary prefers a cool, even cold, sunny location where humidity is high.
It dries out quickly in an indoor growing environment but that doesn’t mean you should water it more, because that will only lead to root rot and killing the plant. In fact, the soil should be kept on the dry side. To add humidity, place the plant on some pebbles in a saucer filled with water.
Or, and this is not research-based but a wise Minnesota Master Gardener does the following technique and it has never let her down. She puts her rosemary plant in the kitchen sink and turns the sprayer on giving it a good “shower,” then lets the water drain out. Then it goes back in a sunny window until it is approaching dryness and then it gets a shower again.
Keep in mind that during the low light days of winter, rosemary won’t do a lot of growing. The plant can be pruned to encourage a tight compact habit. It can also be sheared or pruned into topiaries.
Using a sharp pair of pruners, remove any broken or diseased branches. Cut off 1 to 2 inches of the branches along the outside of the plant to make it more compact. Dear Master Gardener : I was talking with a friend and mentioned planting Allium and he asked if I planted bulbs or perennial Alliums.
I thought all Alliums are bulbs. Are there perennial ones too? Answer : Yes, there are both Allium bulbs and perennials and they have different characteristics. Allium bulbs bloom in late spring to early summer and the perennial (herbaceous) Alliums bloom later.
The bulbs should be planted in the fall, whereas the herbaceous Alliums purchased from a garden center can be planted any time throughout the growing season. Alliums grown from bulbs tend to produce the most dramatic flowers. When Alliums grown from bulbs are done flowering, it is important to let the foliage die back naturally.
When it has turned yellow and withered you can then usually pull it out with a gentle tug. On the other hand, when herbaceous Alliums have finished blooming, just deadhead the flowers — the dense clumps of foliage stay green and lush all season and look like a nice, neat clump of chives. Both are deer resistant and reportedly rabbit resistant, but the rabbits have eaten my herbaceous Alliums and left the ones grown from bulbs alone.
With that said, my Alliums grown from bulbs are the huge Gladiators — maybe those little bunnies can’t reach them! My favorite bulbs include Gladiator, Azure, Mount Everest (white), and Purple Sensation. In my cutting garden I had Allium atropurpureum and Allium nigrum, which are excellent cut flowers. Their stiff stems are easy to arrange and the flowers are very long lasting.
My favorite herbaceous Alliums are Millenium, Blue Eddy, and Summer Beauty. All Alliums prefer full sun and well-drained, even sandy, soil. They are all pollinator friendly — bees and butterflies love them! If gardeners want to plant as many native plants as possible, there is a native Allium called Prairie Onion (Allium stellatum) that grows from a bulb.
It reaches a height of about 2 feet and produces showy pink flowers that bloom from late summer to early fall, eventually forming lovely seed heads. This Allium prefers full sun and dry conditions, so it is well-suited to a rock garden. It can self-sow somewhat aggressively.
ADVERTISEMENT Dear Master Gardener : I was thinking of planting eastern red cedar as a windbreak. Do you recommend it? Answer : It depends. Eastern red cedar (Juniperus virginiana) is an excellent evergreen windbreak and ornamental tree that grows in challenging soils where other evergreens won’t survive.
It is native to east and central North America and the southern half of Minnesota. It is not a cedar, as the name implies, but a juniper. The female tree produces large amounts of beautiful blue, berry-like cones that are a favorite winter food for some birds.
The berries are edible to a certain degree (they should be eaten in moderation and pregnant women should avoid them) and are the flavoring in gin. The trunk of this tree is a lovely reddish-brown and the foliage turns reddish-brown or orangish-olive in winter. Eastern red cedar is very drought and heat tolerant but intolerant of shade.
The University of Minnesota cautions against planting eastern red cedar and all junipers within a few hundred yards of apples, hawthorns, and other plants in the Rosaceae family. It is an alternate host for cedar-apple rust, a fungus that forms bright orange to brown balls on branches and can cause some crop damage to apple trees. Eastern red cedar should not be planted near apple orchards.
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.
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