You’d think that we gardeners would spend the winter months curled up by the fire, perusing seed and bulb catalogs and daydreaming about our gardens in the warmer months ahead. That’s well and good from about Christmas to New Year's, and then in mid-January we start to get the itch — you know the one — our fingernails are just too clean and it’s time to get our hands in the soil. A great way to satisfy your green thumb during the winter is to tackle three classic indoor gardening projects: terrariums, topiaries and bonsai.
Terrariums
As temperatures cool, I turn my attention to the many ways I can enjoy the garden indoors. Houseplants are a popular option, but if you are like me, my woeful neglect of the plants often leads to their quick demise. I suppose that is why I am so excited about terrariums. These houseplant arrangements are simple to assemble and the best news is that they will pretty much take care of themselves.
I have a terrarium on my desk that has thrived for months with low light and no additional water. It's not so much a miracle as it is the science of nature. The plants inside the terrarium create their own miniclimate, transpiring water vapor that condenses on the glass and then flows back into the soil. Science aside, I find a terrarium fascinating to look at, like a miniature landscape in a jar.
Don't be intimidated by the process of building a terrarium. With all the supplies in hand, you can put one together in a few hours.
Materials:
- Wide-mouth glass container
- Something to cover the jar top such as clear plastic wrap, a pane of glass or Plexiglas
- Potting soil
- Small plants
- Pea gravel
- Watering can or spray bottle
Directions: Select a container for the terrarium. For easy access, choose one that has a wide mouth. A fishbowl or aquarium is a good choice. I used an apothecary jar with a glass top. If your container does not have a lid, you can cover it with clear plastic wrap, a piece of clear Plexiglas or a sheet of glass.
To avoid insect and disease problems, wash the gravel with hot water and use top-quality, sterile potting soil.
Fill the bottom of the container with about 1 inch of gravel. If your container is especially deep, you may want to use 2 or 3 inches.
Top the gravel with 3 inches of soil.
Now comes the fun part: planting the landscape. When you choose plants, select varieties that all have the same growing needs when it comes to light, water and humidity. Slow growers with small leaves are best suited for the confines of a terrarium.
Remove the plants from their pots and plant them in the terrarium just like you would in the garden. Place the taller plants in the back, mid-size plants in the middle and low-growing things like moss toward the front. If possible, keep the foliage away from the sides of the container. Once you have the plants in place, moisten the soil lightly and put the lid in place.
How often you will need to water your terrarium depends on how tightly the lid fits. A loose-fitting lid lets moisture escape. A good indication of when to water is the condensation on the glass. If there is no condensation, water the soil very lightly. If there is heavy condensation, remove the lid to allow the terrarium to air out.
The neat thing about terrariums is that you are only limited by your imagination. Add large rocks to represent craggy mountains or small mirrors for ponds. You can even create a desert landscape with succulents and cacti. Good terrarium plants include:
- Acorus
- African violets
- Creeping fig
- Moss
- Maidenhair spleenwort
- Needlepoint ivy
- Oxalis
- Peperomia
- Prayer plant
- Peacock moss (Selaginella uncinata)
Topiary
Topiary can be described as the art of clipping shrubs into ornamental forms to create living sculptures. The word comes from the Latin word topiarus, meaning landscape gardener. This artful form of gardening can be traced to 1st century A.D. Roman gardeners. During the Renaissance it was a mainstay of formal European gardens, and topiary plants are still in high demand today.
I like topiary because, in spite of its rigid appearance, it is quite flexible in application. A standard topiary is an excellent choice for punctuating an entry or, when used in a series, to create a sense of rhythm. And of course, the fantastic forms one can create are a natural for bringing your garden a touch of whimsy.
The gardener Rosemary Verey grew several burning bushes (Euonymus alata) as standards lined up along a central pathway in her garden in Gloucester, England. In fall these lollipop-shaped topiaries ignited the path with fiery red foliage. One day when I was visiting she told me with a wry grin that she was encouraging everyone to call them “great balls of fire.” What great inspiration to get out the shears and start clipping!
I always enjoy discovering new and interesting plants. Angel vine is a vigorous climber ideal for training into topiaries. Its formal name is Muehlenbeckia but I think it’s easier to remember it by its common name, Angel vine or Wire vine, a name taken from its tiny, wirelike stems. Usually plants that look this delicate can be fussy, but don’t let its appearance fool you. This little guy is tough and is a rapid grower.
Angel vine is native to the Mediterranean region so it’s accustomed to hot, dry conditions. I think that’s why it’s so ideally suited to our homes because, particularly in the winter, the air can become hot and dry. It can also withstand the caretaker who forgets to water it from time to time.
In milder climates this plant is an evergreen vine that can grow outdoors reaching lengths of 20 to 30 feet. That’s why it’s so well suited for growing on wire frames indoors. It’s easily trained into a variety of shapes and forms and since it has a tendency to sprawl, you can keep it in check simply by giving it an occasional haircut.
Other plants that make good indoor topiaries include ivy, rosemary, thyme and lavender.
Bonsai
Now, I have to be honest: Most of what I have learned about bonsai is not from hands-on experience but rather from interviewing experts and observing their handiwork. One of the most interesting aspects of this form of garden art is that you are creating a landscape in miniature that looks like it has been there forever.
The name bonsai is from Japanese and means “potted plant.” If you are interested in learning more about bonsai, look for programs offered by Cooperative Extension agencies or local garden centers or even botanical gardens. Of course there are many books on the subject, or you can check out The Bonsai Site for more information.
One last tip I will share with you: Get a good pair of scissors, like pruners, because you are going to use them. Hopefully these three forms of indoor miniature gardening will help satisfy your green thumb this winter.
P. Allen Smith is the CEO of Hortus Ltd., a media production company responsible for two nationally syndicated half-hour television programs, numerous magazine columns, a popular Web site, a best-selling series of garden-design-lifestyle books, lecture series and news reports that air on stations around the country as well as on The Weather Channel. He is also the principle in P. Allen Smith and Associates, a landscape design firm.