Q: I think that I will try to keep this year's amaryllis and persuade it to bloom again next winter. Can I cut off the flower stalk now that it has finished blooming? What about the leaves?
Q: I want to try keeping my poinsettia for next year. I remember something about putting it in a closet, but not exactly what. Do I do that now?
A: Both amaryllis and poinsettia can bloom again next winter. In order to have that happen, they will need to be treated differently next fall. But not now, both plants need the same things. Both will be happy as sun-loving house plants. Find your plant a spot in a south or west window. If there is foil or colored plastic around the pot, remove it. Add a saucer under the pot if one does not exist now.
If you want to repot either an amaryllis or a poinsettia because you own a nicer pot, that is fine as long as you do not choose a bigger pot. Both plants must have their roots crowded. For an amaryllis a small pot is critical; it will not make flowers if its pot is too big. The easiest way to judge what size pot an amaryllis needs is to look at the diameter of the bulb. If there is just enough room for an inch of potting soil around the bulb, the pot size is perfect.
Water both amaryllis and poinsettia often enough that the soil stays moist. Usually that means giving the plant a drink as soon as the top of the soil looks or feels dry. If after the drink some water drains into the saucer, the drink was too big. Next time, water enough to wet the dirt but not make a puddle under the pot. Expect the plant to need bigger and bigger drinks as days grow longer and as the plant grows bigger. Fertilize it a little.
Cut off the flower stalk of an amaryllis as soon as you like. Cut as close to the bulb as possible, since the whole stalk is dead. It will dry up and shrink to nothing over the next few months. New leaves will appear, one at a time. By the end of summer there will be at least four long leaves; a big bulb will make eight or ten. Tying them to a stake will eliminate their flopping far and wide. Treat the amaryllis like a tall green house plant until August.
A poinsettia will keep its good looks for awhile, perhaps even another two or three months. When green leaves or red bracts begin to look tired out, it is fine to start pruning. A poinsettia will begin to grow new leaves any time now, gradually turning itself into a bigger plant.
Prune a poinsettia as much or as little as you choose. For example, if one branch grows taller than the others, cut off half of it. If you cut just above a leaf, a new branch will grow at the base of that leaf. If you cut below all the leaves, a new branch will start from an invisible bud on the stem. Sometimes a poinsettia grows in an attractive shape; sometimes it grows tall and scrawny. It always is reasonable to prune a poinsettia by cutting off half of all the stems that are too tall. If the shape is nice but the red bracts (which look like flower petals but really are leaves) are fading to tan, cut off just the bracts. Enjoy the poinsettia as a leafy house plant until September. I will offer directions for next winter's flowering of both these plants at the end of summer.
Q: I think that I want some of those tall grasses in my garden. Is it possible to grow them from seed, so that they cost less than buying them as plants?
A: It is not only possible but easy. Most of my ornamental grasses have come from seed. If the seeds are planted in early spring, the plants will be big enough to go in the ground for their first summer. I have grown both annual and perennial grasses, but the perennial ones are easier for me.
I have not found that annual grasses reseed themselves, so that has meant planting seeds and setting out fresh crops every year. If you are interested in trying annual grasses, however, there are several which look very nice for their single year in the sun. I have grown — though usually not more than once —hare's tail grass (Lagurus), squirrel tail grass (Hordeum jubatum), black-awned wheat, and various colors of millet.
Among my favorite perennial grasses are these: Prairie switch grass (Panicum virgatum) is tall and graceful from summer through winter, with delicate sprays of small seeds.
Tufted hair grass (Deschampsia caespitosa) is an equally graceful spray, although only two feet tall.
Quaking grass (Briza media) also is short, with seedheads that hang like little hearts.
Prairie dropseed (Sporobolus heterolepis) is smaller yet, a bunchgrass that enlarges its clumps very slowly.
Melica altissima purpurea, which has no common name except melic, is tall, imposing and statuesque.
Calamagrostis 'Karl Foerster' and 'Overdam' make tall bunches which stand erect all winter. Both are cultivars which must be grown from plants, not seeds.
Silver spike grass (Stipa calamagrostis) probably thrives only because it is protected by a house wall.
Although blue oatgrass (Helichotrichon sempervirens) and several kinds of Miscanthus are supposed to be hardy, they were not for me. Mexican feather grass (Nassella tenuissima) is probably the most beautiful grass blowing in the wind that I have ever seen. It died out after a few years; then I learned that where it lives, it can be extremely invasive. Years ago I grew tall wheatgrass, which scattered its seeds on the lawn. I am still digging them out.
I tried the little balls of blue fescue (Festuca glauca); they were healthy but not to my taste.
To grow grasses from seed, allow six weeks for them to grow indoors before transplanting to the landscape. Use deep pots to develop healthy root systems. Scatter seeds thinly on the surface, since they need light to germinate. Once planted outdoors, ornamental grasses need sun and good drainage. Always take it easy on nitrogen fertilizer so that they do not grow soft and floppy.
The winter pause in gardening may give us time to think about what we are doing and why. Or it may not. I feel comradeship with the British garden writer Anna Pavord, who has spent many years playing in the dirt. She says, "I don't feel I have to burrow around in my subconscious for reasons to garden. Fortunately, nobody else seems to feel the need either. Psychologists and psychiatrists leave us alone with our happy mania. My own theory about this … is that the act of gardening itself is what keeps you out of the hands of the shrinks in the first place." Yes. Many a gardener has called it cheap therapy.