Friday, March 29, 2013

Pelargoniums and Geraniums

Members of the Plant Family Geraniaceae

Botanical name: Pelargonium hortorum

Garden Geraniums (sometimes called zonal geraniums), sold at local plant nurseries are actually Pelargoniums.  They are perennials bearing numerous bold, beautiful clusters of hot pink, deep red, salmon, or white flowers, with vibrant deep green leaves which are equally as pretty. 

In most places, Garden Geraniums bloom from April to mid-May and are used as annuals.  Because we rarely experience below-freezing temperatures, in Florida they bloom almost year round.  Cover or bring plants indoors when temperatures fall below 45°F.   

 Garden Geraniums are easy to grow, and are not very picky about soil type, but it must be well-draining.  They are perfect for containers or planting directly in the ground.  They can also be grown indoors with at least four hours of direct sunlight.

 They require minimal watering except during hot, dry spells, and providing good air circulation will prevent powdery mildew, and other diseases.  Geraniums thrive in full sun, but will also do well in partial shade.  Most geraniums are native to southern Africa, and are best suited to very warm climates. However, some are hardy to Zones 7-8.

 They can be propagated by taking cuttings in summer, and by division in spring or fall, and can grow to 3’ in height.

Here’s a brief history on how the botanical name confusion began:  Pelargoniums and Geraniums belong to the Plant Family Geraniaceae.  Originally, they also belonged to the same Plant Genus Geranium.  Carl Linnaeus switched some plants from the Geranium Genus to a new Genus: Pelargonium.  This new plant name just never caught on, and so Pelargoniums continue to be called “Geraniums”. 


Botanical name:  Pelargonium domesticum

Scented-Leaf Geraniums are another type of Pelargonium.  Most are succulent, perennial shrubs in their native habitat.  Scented-Leaf Geraniums are not usually grown for their flowers, and leaves come in a variety of shapes and sizes from velvety, to curly, to thick and hairy.  Their leaves can be very pretty and come in a range of shades from gray to lime green.

Scented-Leaf Geraniums are only hardy in Zones 10 and 11, but can be grown as houseplants if provided plenty of sunlight.  Allow plants to dry out between watering.  Most varieties are about 2-3’ tall, and 1-3’ wide.  There are also a few dwarf varieties. 

Scents, which come from the leaves, include Apple, Chocolate, Chocolate Mint, Lemon, Peppermint, and Rose, among others.  Sandy, well-draining soil is preferred because a soil too rich will minimize their scent. 

Scented-Leaf Geraniums rarely have problems with pests or disease.  Plants are edible, and can be used to add flavor to foods, especially jellies and other sugary treats such as ice cream, butter, or tea.  Leaves also lend well to making potpourri.  Additionally, leaf oils have been found to have a relaxing affect, and are used in aromatherapy.

The tuberous roots of some Pelargoniums have long been used for medicinal purposes.  Most commonly, to treat intestinal ailments such as Chron’s Disease.  Other uses include relieving cold and flu symptoms, kidney problems (it is a diuretic), and wound care. 


Botanical name:  Pelargonium peltatum

Ivy-Leaf Geraniums are often used in hanging baskets due to their trailing habit.  They otherwise bear a striking resemblance to Garden Geraniums, except for their leaf shape, and flowers are not quite as showy.  Caring for Ivy-Leaf Geraniums is the same as for the Garden Geraniums and Scented-Leaf Geraniums.  Pelargoniums and Geraniums are very low maintenance plants.

Botanical name:  Pelargonium x domesticum

Regal Geraniums are often referred to as Martha Washington Geraniums because they were arguably the most popular variety in the 1800’s.  The primary characteristic differentiating them from Garden Geraniums (Pelargonium hortorum), is their flowers have a more pansy-like shape.  Like the other Pelargoniums, Regal Geraniums are beautiful, and very easy to care for, rarely affected by pests or diseases.  They require well-draining soil, and are somewhat drought tolerant.


Botanical name:  Geranium spp.
(spp. stands for “species plural” – the Genus is Geranium, not Pelargonium)

True Geraniums are often referred to as Cranesbill Geraniums because seed pods are said to resemble a crane’s bill.  Other common names include Perennial Geraniums, Hardy Geraniums, and Woody Geraniums.

True Geraniums are spreading, but not invasive, perennials.  Most have attractive, toothed foliage, and cup shaped flowers.  The most common colors are blue and purple, but can also have magenta, pink, or white flowers.

They grow well in Zones 4 - 8, and are three inches to two feet tall.  The most commonly grown type is a dense ground cover.  The leaves are usually serrated or lobed, and 1” flowers on thin stems attract butterflies and bees.

As with Pelargoniums, True Geraniums require little to no maintenance once established.  Dividing plants will keep them from spreading, and shearing will encourage new blooms while keeping plants neat and attractive.

Good air circulation is recommended.  High humidity may cause mildew and rust, and slugs can attack young plants. 

Article Written by Jill A. Tobin, 03/29/2013



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