ASK A MASTER GARDENER
Dear Master Gardener,
I was given a plant called kalanchoe as a gift and was wondering how well it keeps as a house plant.
Answer: Kalanchoe is a succulent plant that is easy to grow and makes a good houseplant. They are frequently found for sale around the holiday time. The kalanchoes that produce flowers are usually yellow, orange, red or pink and bloom a long time. If you decide to buy one as a gift, select one that fills the container and is just about to bloom.
To take care of your kalanchoe and prevent it from getting weak and leggy, provide it with as much sunlight as possible. It does well in daytime temperatures of 65-70 degree, nighttime temperatures of 50-60 degrees and normal household humidity. Water the plant thoroughly and then let it dry out before watering it again. They rot easily, so don’t over-water them. Like most houseplants, kalanchoes should be fertilized throughout the normal growing season of March through September. Use a liquid fertilizer meant for flowering houseplants after the plant is done flowering. After your kalanchoe has finished flowering, pinch off the dried flowers.
Dear Master Gardener,
I would like to create a terrarium this winter. How do I go about it and what type of plants should I get?
Answer: Traditionally, a terrarium is an enclosed, glass or plastic container used for growing small plants indoors. Nowadays people use open containers too, such as a glass fish bowl, fish tank or many other interesting containers. You can use anything from a unique garage sale find to a specially designed terrarium, but the container should be clear glass or plastic. If you have a closed terrarium, more humidity will be retained and you will water less frequently. The cover should be transparent. Open terrariums will need more frequent watering to maintain the humidity level needed by some plants, but they are less prone to disease.
To begin, make sure your terrarium is very clean and dry. As a general rule, about one-fourth of the terrarium should contain the drainage material and growing medium. Place activated charcoal and pebbles in the bottom. They may be mixed; however, the charcoal will usually be more effective in eliminating the chemicals that could harm plants if you put a half inch layer above the layer of pebbles. Charcoal is essential in covered terrariums. Place sphagnum moss over the layer of pebbles and charcoal to prevent the growing medium from mixing into the drainage area. Next, place the growing medium, which must be clean, well-drained, and high in organic matter. A good choice is a prepackaged mix of peat moss, vermiculite and perlite. You need at least 1-1/2 inches of growing medium.
Terrariums grow well in average indoor temperatures. If you plant cacti and succulents, then your terrarium needs to be in bright, direct light. Most other green plants will do best in bright indirect light. Typically a closed terrarium will need to be watered about every four to six months. After watering do not put the cover back on until the foliage is dry. Open terrariums need to be watered more frequently. Always water lightly because over-watering may result in root diseases. It is better to error on the dry side. Because you do not want your miniature plants to grow quickly, adding fertilizer is usually not necessary. You may want to use a water-soluble fertilizer at one-fourth strength in the summer months if you are using a soilless mix.
When choosing plants for a terrarium, choose those that have similar water, light and temperature requirements. Most plants that are suited for terrariums need high humidity. Those that do not need humidity, such as cactus and succulents, are better off in open containers. From a design perspective, choose plants that vary in size, color and texture. A low, coarse textured plant makes a good focal point near the front. Try not to have too many variegated plants or your terrarium will look too busy. If you are putting plants in a closed terrarium try to make sure the leaves do not touch the sides of the glass. You may want to add stones, wood, bark or other natural materials to add interest to your design. With the growing popularity of fairy gardens it is easy to find cute accessories, such as fairies, gnomes, miniature garden items, mushrooms or frogs, just to name a few.
To keep the plants in your terrarium as healthy as possible, make sure to remove any leaves that are wilting and leaves that have fallen. Pinching the tips of the plants will keep them smaller and usually promotes better growth.
Dear Master Gardener,
We have built a house on a city lot devoid of trees. We would like some trees but health issues make caring for them difficult. Would you suggest some trees we should eliminate for that reason?
Answer: There are no plants that are totally maintenance-free, but some are more so than others. Some are simply not suitable for small city lots, such as weeping willows, cottonwoods, silver maples and boxelders. All of them grow rapidly into enormous trees and have weak, soft wood that breaks easily in the wind, often damaging structures and vehicles. In addition, weeping willows’ whip-like branches break off so easily that they become a litter problem for owner and neighbors alike. Cottonwoods produce copious “cotton” that litters, silver maples have roots that push up sidewalks and produce lawn humps that make mowing difficult, and boxelders produce many, many seeds. Acorns from oaks, samaras (the helicopter like seeds) from maples and cones from pines may be offensive litter to some but are charming to others.
Other trees to eliminate are those subject to serious insect and disease problems that prematurely kill or disfigure their hosts. Oak wilt, for example, has killed thousands of red oaks. White and bur oaks, on the other hand, seem to be oak wilt resistant. Dutch elm disease has virtually eliminated elms in Minnesota but new cultivars are being developed, which may return that beautiful species to our midst. In recent years many green ash trees are succumbing to ash yellows. Colorado blue spruce, a favorite of many, is almost always short-lived, succumbing to numerous insect and disease problems that disfigure and ultimately kill. European mountain ash is unusually susceptible to fire blight, heat and drought, though it does relatively well in mixed woodlands. Eastern red cedar is susceptible to and is host for cedar-apple rust, unsightly on cedars and spreading to apple and crabapple trees. Other trees, such as poplars, aspens, plums and cherries, tend to send up suckers which invade lawns and flower beds.
You may be thinking that this list encompasses most trees you were considering. Notice, however, that many — if not most of them include just one species within a genus, such as red oak within the oak species, but not all oaks. Other species contain new cultivars in which objectionable qualities have been bred out. Buy your trees from local dealers who know their trees and cultivars and will not stock trees known to be problems in our areas. In addition, read the tree labels carefully and check out the University of Minnesota Extension website for more details on specific trees and their cultivars.