Pelargonium tetragonum

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Botanical Name
Pelargonium tetragonum
Geraniaceae - The geranium family.
pe-lar-GO-nee-um tet-ra-GO-num
Common Name(s)
English: Square-stemmed pelargonium
Plant Group
  • Shrub A woody plant of relatively low height, having several stems arising from the base and lacking a single trunk; a bush.
  • Veld Flower Small veld flowers of interest, rather than for their usefulness in the garden. Some of these plants have garden potential, particularly for less formal garden situations.
Plant Size
  • Medium
    Tree10m to 16m
    Shrub1m to 2m
    Perennial/ground cover40cm to 60cm
    Bulb40cm to 60cm
    Succulent40cm to 60cm
  • Partial Shade The area is in shade for part of the day and in full sun for part of the day.
  • Sun The area is in full sun for all or most of the day, all year round.
General Information
  • Drought Tolerance: High The plant is well adapted to arid conditions; it can survive long periods of drought and high temperatures without extra water.
  • Evergreen Plants that have leaves all year round.
  • Frost: Half-hardy The plant is able to survive low temperatures and some frost but requires protection against severe frost.
  • Water Wise Plant species originating from low rainfall regions that require less water to survive and thrive than other plant species.
Specific Information

Pelargonium tetragonum is sought after by collectors for its unusual growth form, rather than for its garden usefulness. It is adapted to grow in arid habitats, making it an unusual specimen for a water-wise garden. The plant branches out from the base and tends to sprawl, unless supported by other vegetation, in which case it may reach a height of 2 meters. The succulent, jointed stems are three to four angled and almost leafless. When the hairy, palm-shaped leaves do appear, they remain on the stems for only a brief time before yellowing and falling off.

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pelargonium flower - the flowers occur in pairs, each with only four petals, the upper two petals being appreciably larger than the lower pair, and streaked with red or maroon

  • Spring to Summer Plants will seldom bloom for the entire season as given in the list, but should flower during a period within these parameters.
  • pink
  • ceam
Growth Rate
  • Slow to Moderate Specifying growth rate can be very misleading as there is considerable variation of growth rate depending on type and species of plant, available water, supplementary feeding, mulching and general care, as well as the plants suitability and adaptability to the garden environment.
Plant Uses
  • Container Trees, shrubs and ornamental species that can adapt to growing in a restricted environment.
  • Filler Either a fast growing tree or shrub used temporarily to fill in an area while the permanent plants grow to a desired size, or a plant used to fill gaps in borders or beds.
  • Pot Plant A plant that needs a protected environment on a patio or indoors.
  • Rock Garden An area constructed of larger rocks, arranged naturally, to emphasise the use of stones as a main element. Generally plants used do not need a lot of care.
  • Wild Garden An indigenous garden planted for the benefit of wildlife and birds. Provides food, water, a variety of mini-biomes and no poisonous¬†chemicals are used.
Distribution and Habitat

found only within a strip parallel to, but inland from the south-eastern coast of South Africa, extending from Worcester in the Western Cape to Grahamstown in the Eastern Cape, its distribution extending across both winter and summer rainfall climates, in semi-karoid scrub and dry, rocky spots

Planting Suggestions

Pelargonium tetragonum is a dweller of arid habitats, and will rot if over-watered. The soil must be very well-drained and it does not need feeding. Plant in a sunny dry position, preferably in the light shade of a shrub through which it can climb, as it often does in its natural environment. Water sparingly until established, then seldom, if at all. In wetter climes it is better to keep this curious pelargonium in a pot or container.

Medicinal Uses

No data found

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I have one of these plants in my south-facing greenhouse in Leicester, UK.
It shared the bed with a thug of Passiflora Antioquiensis, which I just got rid of because it overwhelmed my space! I'm just wondering if the p.T. will do as well as before....It's had lots of water (tap & rain)over the 10 years I've had it, but on reading your site , I will give it much less.
The bed is of poor, stoney 'soil' and I was going to add some compost, now the Passiflora has departed, but assume you would not advise this? Before I read your advice, I gave it water & pruned it heavily, leaving the flower buds. to open. Hope to hear from you. Jenny Cook

Hi Jenny

Well it seems you have broken all the rules quite successfully so I am hesitant to suggest any changes. The stony soil is good and is probably what prevents water-logging, which would cause rot. A little feed of compost shouldn't do any harm as the plant has been in place for some years. I am interested in how well your plant flowers. Some plants from drier areas often do not flower as freely if they receive more water than they do in their natural habitat. If you do not get many flowers you could try reducing the water, especially during winter, to see if that encourages blooming. However, if the plant is thriving, you must be doing the right thing.

My own two specimens have been hit by a bug or disease. Many of the stems have completely dried out leaving just a few healthy bits and pieces. I am in the process of trying to save what is left. I feel quite envious when you say you have pruned yours!

I don't think the removal of 'the thug' should make a difference, but keep an eye on the plant just to make sure.

Kind regards

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