Past Articles Library | Geraniums: Types, Planting, and Propagation
Every year planters, hanging baskets and even landscapes can become the home of the geranium. This humble plant’s origins began in South Africa and for over 300 hundred years have been a part of the horticulture landscape.
There are four basic types of geraniums. This includes ivy-leafed, zonal, regal, and scented. Each one of these types has their own purpose in any horticulture plan.
The ivy-leafed geranium (Pelargonium peltalum) or vining geranium is a plant whose trailing natures make it perfect for hanging baskets and window boxes. The leaves are waxy and the flowers are small. This type of geranium benefits from pinching back to encourage branching out. If shopping for an ivy-leafed geranium check out ‘Summer Showers’ and ‘Balcon.’
Zonal geraniums are a hybrid created between Pelargonium inquinans and Pelargonium zonal. This geranium’s leaf has a special treatment, which includes scalloping or variegation of the leaf edge. If the leaves are crushed or bruised, a strong aroma is produced. If looking for this type of geranium try ‘Star,’ ‘Cameo,’ ‘Gypsy,’ and ‘Mrs. Henry Cox.’
Regal geraniums (Pelargonium x domesticum) are a variety whose growth habit is uncharacteristic when one thinks of this plant. It grows in an upright manner that forms a shrub-like shape. The leaves are stiff and it resembles an azalea. This type of geranium is sold as an indoor variety due to the fact that it is not heat tolerant.
Scented geraniums are valued, not for their small flowers, but instead for their scented foliage. This foliage is a gray-green color and is used in many different culinary dishes, potpourris, and sachets. Examples of scented geraniums that can easily be found include the apple geranium and rose geranium. The apple geranium has a trailing growth habit and an aroma of fresh apples. The rose geranium has hairy, deep-green leaves that are divided with toothed edges and smells like an heirloom rose.
A unique geranium that falls under the scent geranium category is the ‘mosquito geranium.’ This geranium is created when a scented geranium has a gene of the Citronella grass spliced into its genetic code. The smell of citronella is released when the leaves are rubbed or crushed. It is promoted to repel mesquites but there is not proof for this claim.
Geraniums can be started from seed or cuttings and depending on the type you desire will determine how they are started.
Once the plant is brought home, it will need to be planted in its new home. Geraniums should only be planted after the local frost-free date. Also geraniums should only be planted in a well-drained soil that is located in a bright sunny area. To make the transition easier for the plant, gradually expose the plant to its new location through the process called “hardening off.”
While the geranium is getting used to its new location, it is a good time to prepare the soil. This step needs to be done whether the plant is going in a container or in the flowerbed. Begin to enrich the soil by mixing in 1 inch of course sphagnum peat moss, partially rotted manure and/or compost into the top 3 inches of earth.
Once the soil is prepared, it is time to plant the geranium. Gently remove the plant from its container and loosen the roots with the fingers. Create a hole for the plant that is no deeper than the original depth of the geranium. Place the geranium in the hole and check the depth by putting the hand on top of the soil surrounding the geranium’s root mass. Push the hand across to the garden soil level. If both levels meet, the soil level is correct. If they do not meet adjust the soil level as needed.
After the geranium has been placed in the hole and the soil has been filled in, gently push the soil down and around the root mass. Water the geranium in and apply a liquid fertilizer, such as 20-20-20 or 15-30-15, according to package directions. Water this fertilizer into the soil so that it reaches the roots and does not burn the plant.
Continue to check the soil moisture and water accordingly. Deadhead or remove spent flowers, as they appear to promote additional flowering.
Geraniums can be saved from one year to the next through digging up, stem cuttings and hanging upside down. Each technique has advantages and disadvantages. Digging up consists of replanting the geranium in a pot and bringing them indoors for the winter. Cuttings can then be taken from these same plants in the spring but space, adequate light, and time is required to keep the plant alive over winter. Another approach to planting is to hang the geranium upside down in a cool room after all the soil has been removed from the root mass. Come spring this plant can be planted in a container, watered and exposed to the light. The plant will resume growing as it did before. The disadvantage to this technique is that it requires space and a humidity of 85 to 90 percent.
The last approach consists of taking cutting from the geranium around August. These cuttings need to be 3 to 4 inches in length. Remove all the lower leaves and dip into a rooting hormone. Push cutting 1 inch down into perlite, sand or peat moss and water in completely. Keep the rooting medium evenly moist and in 3 to 4 weeks the cutting will have rooted and ready for the garden bed.