Looking for a new and interesting herb for your windowsill? A plant that’s relatively easy to grow and propagate indoors, that grows lush and green and smells great, and that offers a wide variety of visual qualities and scents to match your decor and preferences? If you haven’t tried growing scented geraniums (Pelargonium spp.), you’re in for a treat.
Scented geraniums aren’t really very new: I remember a rose geranium in Grandma’s cool room when I was a child. What’s unique about these plants is that they mock other scents—rose, lemon, lime, pine, even coconut. Although they do produce small blooms, scented geraniums are grown for their fragrant leaves rather than their flowers, and the variety of leaf shapes and textures and the many shades of green can add abundant interest to your indoor gardening.
Best Varieties for Indoors
Better garden centers are now carrying good selections of scented geraniums, or you can purchase them by mail order.
I classify scenteds into six groups according to fragrance: rose, fruit (which includes all the lemons), spice, mint, pine, and pungent. If you have only a small area on a windowsill, you’ll probably want to consider the fruit group. They all have small leaves, they grow more slowly than the others, and the mature plants are smaller. Varieties in the fruit group that are fun to use in dish gardens and topiaries include fingerbowl, ‘Crispum’, golden lemon, ‘French Lace’, lime, and strawberry.
If you have a corner with a southern and western window and some hanging basket room and floor space, you can choose larger varieties from all the groups. Here are the varieties that do well for me indoors.
• Rose: old-fashioned rose, peppermint rose, and ‘Skeleton Rose’
• Fruit: ‘Mabel Gray’, ‘Prince Rupert’, and ‘Apricot’
• Spice: cinnamon and nutmeg
• Mint: pungent peppermint
• Pine: fern leaf, staghorn, and ‘Dean’s Delight’
• Pungent: ‘Clorinda’, ‘Mrs. Kingsley’, ‘Old Scarlet’, and ‘Scarlet Unique’
Plants Suitable For Hanging Baskets
• Rose: ‘Atomic Snowflake’, ‘Attar of Rose’, and ‘Snowflake’
• Fruit: apple, coconut, and filbert
• Spice: ‘Old Spice’ and ‘Golden Nutmeg’
• Mint: ‘Chocolate Mint’, ‘Mint’, and ‘Joy Lucille’
• Pine: ‘Fair Ellen’ and ‘Oak Leaf’
• Pungent: ‘Little Gem’
Soil and Fertilization
Scented geraniums need a light, well-drained potting soil that has been sterilized so that it will be weed- and disease-free. You can buy such a mix at any garden center. Adding a cup of perlite per quart of potting soil will promote aeration of the roots.
Scented geraniums are like people: they need food. And as with people, too much food is as bad as too little. I find that a general-purpose, water-soluble fertilizer (20-20-20) applied twice a month is all that’s needed to keep my scenteds healthy. Easier still is Osmocote, a time-release pelleted fertilizer that is placed on the soil. Every time you water, the appropriate amount of fertilizer is released; one application lasts for as long as three months. Both of these products are available at garden centers.
Scented Geranium Maintenance
Watering is an essential aspect of scented geranium care. As a rule, the soil 1 inch below the surface should be allowed to become almost dry before you water. (If you wait until the foliage starts to droop, the plant probably won’t die, but the leaves may yellow and fall off.) If the soil is constantly wet, the roots will die from oxygen starvation. Each time you water, apply enough so that the excess runs out the bottom of the pot. The necessary amount and frequency of watering vary according to the type of heating system you have (some dry the air more than others), temperature of the room, amount and nature of light, type and size of container (clay pots draw moisture from the soil; plastic pots do not), and whether a plant is by itself or one of several in a group.
Because moisture is lost more slowly in the cool of the night, plants watered then may stay too wet; the solution is to water in the morning. Watering should be at the soil level; misting the plants can cause the leaves to become spotted. However, scenteds grow best in relatively high humidity. Unless the humidity is normally high where you live, growth will be enhanced by placing pots in waterproof trays of gravel filled with water to just below the top of the gravel. Positioning the pot above rather than in the water helps to keep the roots from rotting.
Groom your scenteds regularly, and topdress the soil with fresh potting mix, pebbles, bark, or marble chips to give the plants a clean look. Trim the plants to promote lush growth and make them bush out nicely. In general, allow three pairs or sets of leaves to form before pinching off the new growth; smaller-leaved varieties, such as ‘Crispum’, may be pinched more often. You may save healthy leaves to add to potpourri or jelly.
Do take time to touch the leaves of your scented geraniums and enjoy their aromas. After all, this is what makes them different from other plants, and what makes them such great conversation pieces.
Lighting Scented Geraniums
A garden room or solarium is ideal for growing scented geraniums. You’ll need to shade it somewhat during the summer, but in winter, your scented geraniums will thrive.
Scented geraniums should receive direct sunlight during at least half of the daylight hours. If you don’t have a garden room or a window with good light, you can still have beautiful scented geraniums with the help of artificial light. Plants can grow and be happy, even in the bleak, gray winter, with a combination of natural and artificial light. Special fluorescent tubes that simulate the sun’s light—full-spectrum tubes or “grow lights”—are available at garden centers and hardware stores. You can substitute regular cool white fluorescent tubes, which are considerably less expensive, but you’ll need to keep them on a couple of hours longer and hang them closer to the plants than you would full-spectrum tubes.
Hang regular fluorescent tubes 6 to 12 inches above the tops of the plants. If the plants begin to contort or bunch, they’re getting too much light; raise the lights a few inches higher. If the plants become leggy, with long distances between leaf nodes, and the leaves appear pale, lower the lights a few inches. Scented geraniums need 12 to 14 hours of light per day. In winter, I supplement the light from a sunny window with about eight hours of artificial light. An inexpensive timer turns my lights on about 5 p.m. and off about 2 a.m. But keep in mind that the plants also need five to six hours of darkness per day.
Another lighting option, which offers a vast aesthetic improvement if you’re willing to pay the somewhat higher price, is the new high-intensity discharge or metal halide lights. These lights provide full-spectrum light at a higher intensity and over a larger area than fluorescent tubes can, and they are mounted much higher above the plants. For example, a 175-watt metal halide light is sufficient to illuminate a 3-by-3-foot area from a height of about 3 feet above the plants; a 250-watt light covers a larger area and can be raised to about 6 feet. From these starting heights, adjust according to the reaction of the plants, as described above. When you use fluorescent tubes that are hung no more than a foot above the plants, you see more fixtures than plants, whereas high-intensity lights are hung high enough to allow a clear view of the plants. Information on high-intensity lights may be obtained from the suppliers listed below.
Pests and Diseases
Besides using a sterilized potting mix, other strategies for preventing disease include providing good air circulation, keeping healthy plants away from infected ones, and removing dead and damaged leaves. Good sanitation, including frequent weeding, will go a long way toward keeping your plants in good health.
Whiteflies seem to be the biggest pests of scented geraniums. They are tiny, pure white insects that lurk on the undersides of the leaves, and they rise into the air when you run your hand over the foliage. To eliminate them, spray the undersides of the leaves with a mixture of one teaspoon of mild dish detergent in a quart of room-temperature water. This will kill the adults but not the eggs; spray again a week later to take care of the next hatching. This soap spray will also put a damper on fungal growth. I use this treatment as often as once a month, and I don’t find it necessary to rinse off the soap; it doesn’t seem to spot the leaves or hamper growth.
Botrytis, or gray mold, is a fungal disease that appears when conditions are damp and cold. Remove debris that collects at the base of the plant, as it is a prime place for mold spores to develop. If you notice a stem that has turned soft and black, the best course is to dispose of the entire plant immediately.
I can’t stress it enough: keep your scenteds and their surroundings clean, and you will enjoy pest- and disease-free plants.
When you receive scented geranium plants from a mail-order supplier, unpack them immediately. Check for damage or defects, and make sure you’ve received what you ordered. Plants are usually shipped with moist soil which is enclosed to hold both plant and soil in the pot. Remove the wrappings immediately and place the plants in indirect sunlight. Give them a couple of days to adjust before exposing them to direct sunlight, and wait until the soil is almost completely dry an inch below the surface before you water.
Judy Lewis of Manchester, Ohio, has been in the business of growing herbs since 1974. She and her husband, John, currently operate Lewis Mountain Herbs, a thriving farm that includes eight acres of herbs and everlastings and 125 varieties of scented geraniums.