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6 Facts About Regal, Martha Washington Geraniums (Pelargoniums)

Janet has been passionately growing pelargoniums since a child. She's a member of the Geranium and Pelargonium Society.


Martha Washington geraniums, also known as regal geraniums, are quite a popular sight in many nurseries and garden centers when Mother's Day is around the corner.

It's almost as if Mother Nature has strategically timed when these plants are in full bloom and very attractive with the national holiday meant to honor mothers.

Enjoy their wonderful colors when they are at the peak of their flowering time until they last—these plants will display their glorious crowns for just about two months in late spring and early summer.

Generally, you can admire their showy flowers between mid-May and late-June.

During this time, their generous flowering can be so abundant that a great extent of their foliage will remain hidden.

Unlike regular zonal geraniums, regal geraniums need a little more tender loving care. These plants are known for needing some white glove—regal treatment, so to say—but all the work is well worth it once regals are adorned with their pretty crowns.

This article will share several fascinating facts about regal, Martha Washington geraniums along with several helpful tips, so that you can enjoy this plant's striking azalea-like flowers in pots, flower beds and fancy flower arrangements,

Picture of one of my favorite regal geraniums

Picture of one of my favorite regal geraniums

1) Regals Go By Many Names

Regal geraniums are known by many names. Some like to call them regals, some like to call them Martha Washington's or Lady Washington's, and some others call them pansy-flowered geraniums, show pelargoniums or even summer azalea.

Regal pelargonium were also known as "royal pelargoniums" in the late 1800.

For those looking for their scientific name, regals are known as "pelargonium x domesticum" and belong to the Geraniaceae family.

It was L.H. Bailey, who, in 1906, decided to label regals as pelargonium x domesticum to differentiate them from the other types of pelargoniums.

Regals are hybrids and therefore they have quite a diverse heritage. What have they been crossed with?

There's belief that their lineage mainly derives from crosses among pelargonium cucullatum, peleragonium angulosum and pelargonium grandiflorum (Bailey, 1976)

2) They Call Africa Their Home

Where do regal geraniums come from? Their natural habitat are the southern regions of Africa, primarily the western/ southwestern coastal regions by the Cape of Good Hope (Riley, 1963).

It's estimated that around the year 1600, ships transported the first specimens from the Cape of Good Hope to Europe by Dutch trade, and they quickly became a favorite in botanical gardens.

How is the climate in South Africa? South Africa has a typical Mediterranean climate, with mild, rainy winters and warm, dry summers. Generally, temperatures may reach 80 degrees in the summer and 68 degrees in the winter.

The cooling sea breezes of their hometown benefits regals as these plants dislike intense, prolonged heat.

Moisture is also something regals hate as their native lands provided them with sandy soil with excellent drainage.

Don't expect to find regals though growing in the fields of South Africa as wild flowers do: regals do not grow in the wild, they are the product of cultivation.

One of my favorite regal geraniums in my personal collection boasting purple blotches over the top petals.

One of my favorite regal geraniums in my personal collection boasting purple blotches over the top petals.

3) Regals Produce Amazing Flowers

Regal geraniums are mostly known for their spectacular blooms and variety. You may find flowers with petals that are fringed, spotted and semi-double.

You'll often see petals that have dark-pigmented blotches which are especially noticeable along the veins on the upper petals.

The flowers are quite large, measuring on average 2 inches (5 cm) or more across. The term "grandiflorum" seen in one of these plants' ancestors indeed is used to depict plants producing large, showy flowers.

Some of the smaller-flowered varieties with two darker upper petals and three white lower petals, are referred to as "pansy-flowered varieties" because of the close resemblance to pansies.

Flowers come in multitude of vibrant colors such as white, pink, light orange, crimson, mauve, deep burgundy, purple, and lavender. Actual red is not very common, unlike the quintessential red seen in the zonal geranium.

It is courtesy of the work of several German hybridizers that today we can admire these plants with large, colorful blooms.

Carl Faiss introduced several cultivars to California in the 1920s. Other notable names of hybridizers include William Schmidt, Ernest Robert, M. Henley and Clara Sue Jarrett, Albert H. Cassidy, Richard Diener Howard Kerrigan, Fred and Alice Bode, Frances Hartsook, Amanda Brown and her sons to just name a few.

Throughout the many years, it's quite evident that breeding of regals has always focused on the shape and colors of flowers.

4) But They Need Cool Weather to Do So

In order to bloom, regal geraniums require the right temperatures. This can be quite a big obstacle depending on where you live. For instance, the warm nights of the Midwest may be too hot for them.

The thing is, in order to produce their spectacular blooms, regal geraniums need cool temperatures. How cool? In general, they'll appreciate temperatures around 58 to 60 degrees to feel happy and eager to produce blooms.

According to research by Powell and Bunt (1978) it was found that average temperatures exceeding 64 degrees and short 8 hour days caused the flowers of regal geraniums to be completely aborted.

Research by Erwin and Engelen (1992) also reported similar effects with flowering being aborted when the average daily temperatures exceeded 61 degrees.

When day temperatures are too high, regals benefit from lower night temperatures to make up for the heat of the day and maintain a low average daily temperature, suggest Marietta M. Loehrlein and Richard Craig.

It therefore takes the right temperature to enjoy these blooms. For some fortunate folks living in coastal California, regals may bloom in containers nearly year-round.

When the fear of winter frost is over, regals love to be outdoors in the cool spring.

Did you know? Regals love and thrive in the sun, but everything in moderation. A good way to gauge their wellbeing is by touching the leaves. The leaves should ideally feel crisp and a little rough. Soft and flaccid leaves are signs that the sun is too much and the plant is suffering.

Red is not very common in regals as it is in zonals

Red is not very common in regals as it is in zonals

5) Regals Don't Like "Wet Feet"

As other pelargoniums, regals dislike having "wet feet." In other words, they have a fine rooting system and suffer from the effects of overwatering.

In particular, regals particularly resent water when the days shorten and the nights start becoming cold.

This means that you will have to keep an eye on the growing medium you are using before watering. Make sure that it is allowed to dry out in between waterings.

Regal plants need well-drained soil and gardeners may wish to add some perlite to their well-drained mix of high-quality peat for better drainage. Vermiculite is best avoided considering its tendency to compact (Oglevee, 1999).

6) They May Be Prone to Whitefly Infestations

The biggest enemy of Regal geraniums is the greenhouse whitefly. You can use yellow sticky cards to keep track of any adult populations establishing.

As the name implies, these are white little "flies" that tend to be found on the bottom of a regal's leaves. They damage the plant by sucking sap. These flies thrive in areas with no wind.

Persistent infestation cause plants to look unsightly. Affected plants may lose vigor and yellow spots may form on the areas where the whiteflies have fed.

Products used to tackle whiteflies can help, although you may need repeated applications. A hand-held battery-operated vacuum cleaner may help as well considering that it allows you to suck up adult whiteflies.

Careful when watering your regals in not letting water sit on the leaves.

Careful when watering your regals in not letting water sit on the leaves.


  • History and Culture of Regal Pelargonium by Marietta M. Loehrlein and Richard Craig
  • Passion for Pelargoniums: How They Found Their Place in the Garden by Anne Wilkinson and Chris Beardshaw
  • Geranium by Kasia Boddy

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2022 Janet Rolla