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Geranium Rozanne, magnificent ground cover

Geranium Rozanne

Geranium ‘Rozanne’ is a variety with one huge advantage: it’s a perennial. It resists freezing while maintaining incredible ornamental value.

Geranium Rozanne facts

NameGeranium ‘Gerwat’
Trademark – Geranium Rozanne™

Type – perennial
Height – 16 to 20 inches (40 to 50 cm)
Exposure – full sun, part sun

Soil: ordinary but well drained  –  Flowering: May to October

Ideal for ground cover and well suited to growing in pots or pot arrangements, geranium Rozanne also offers a very long-lasting blooming.

Planting the geranium Rozanne

Preferably in fall or spring in a mix that includes geranium-specific soil mix.

Planting geranium rozanneSpace plants around 8 to 16 inches (20 to 40 cm) apart.

  • The Rozanne geranium fears moisture more than it does cold.
  • It loves full sun to bloom as long as possible in an abundant burst of colors.
  • Propagate through crown division in fall.
  • It’s also possible to start new plants from cuttings.

Since Geranium Rozanne is a sterile hybrid, it will never produce seeds.

  • Not having any seeds is an advantage. If it did grow seeds, it would spread and probably turn invasive because it is very hardy and resilient!

Pruning and caring for the geranium Rozanne

Mounding Geranium Rozanne with wood chip mulch.The geranium Rozanne requires next to no care, like other perennial geranium.

Cut back stems eventually after they have flowered in order to trigger production of new flowers and avoid draining your perennial geranium.

Pruning Rozanne ‘Gerwalt’ Geranium

This pruning will also keep your Rozanne from getting leggy and spreading too far: cut branches back by half to trigger new branching out. You can do this in any season, but there are differences:

  • in fall and winter, go ahead and cut them all at once
  • in spring and summer, cut back the longest ones only. Wait for new growth to appear on them. When leaves have opened up on the branches you’ve pruned already, go ahead and prune a few more of the remaining longer ones by half. Repeat until you’ve shrunk the entire bush.

As resistant to diseases as it is hardy, no known disease seems to infect geranium Rozanne.

Geranium Rozanne in winter

Leaves and smaller stems will die back with the cold.

  • Cut them off or remove them delicately.
  • Mulch the base with free-breathing plant mulch such as dead leaves.
  • In spring, new shoots will appear.

Geranium Rozanne in summer

For sustained blooming, water often but make sure excess water drains out.

  • Heat and high temperatures aren’t a problem for this Geranium variety.

Learn more about the geranium Rozanne

This perennial is among the most abundant flower-bearing geraniums. More than anything, it is among those that bloom over the longest period. Indeed, the blooming extends from May up to the first fall frost spells. It can withstand summer heat.

Care, heat resistance and water needs are identical to those of Sunpatiens, another great sun-loving flower.

In a flower bed and also along edges and in rocky ground, geranium Rozanne can serve as excellent ground cover (like the Patricia geranium) and beautiful garden box items.

History of Geranium Rozanne

Geranium Rozanne was first bred and discovered in 1989, by Donald and Rozanne Waterer. They were growing several dozens of Geranium plants which Rozanne loved. One year, a particularly vigorous specimen appeared in their garden in Somerset in the United Kingdom. It flowered profusely the next year from spring to first frost. Rozanne had never seen such a bloom! Parent plants were Geranium himalayense and Geranium wallichianum.

The couple was already familiar with horticulture, since Donald had been born and raised in a family that loved gardening (they had bred many hardy azalea varieties in their heyday). He had managed it and this discovery came after he had retired. They got in touch with flower expert Graham Stuart Thomas.

Graham Thomas was already famed for his work on preserving old English roses heritage breeds. He guided the Waterers towards Adrian Bloom (of Blooms of Bressingham), a well-known horticulturist. After propagating, growing and testing the plant, they were able to patent it as a new development!

Two single Geranium Rozanne flowers with clear white center, purple petals and violet petal veins.Thus the plant was originally protected by a plant patent. The botanical name is actually “Gerwat”, which stands for Geranium and Waterer. “Rozanne” is the trademark name that the plant was marketed under, in honor of Mrs. Waterer.

After 2 decades, this patent has expired in February 2019 (for the United States and GATT signatory countries). It’s now allowed to propagate your own, and even sell them!

It’s a beautiful example of how a passion for flowers can spread the world, since millions of specimens have been sold throughout the world.

Smart tip about geranium Rozanne

You can provide it with geranium-specific organic liquid fertilizer once or twice in the season to increase blooming.

Also, Geranium Rozanne prefers slightly acidic soil rather than alkaline soil, so a good mulch to use is pine bark mulch or even coffee grounds.

Images: 123RF: WDNET, CC BY 2.0: Arend Vermazeren, CC BY-SA 2.0: F. D. Richards, Fr. Ted Bobosh
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  • Victoria Smith wrote on 26 June 2023 at 16 h 57 min

    My Roxanne has got very leggy it’s spreading over other plants how can I remedy this thank you

    • Gaspard wrote on 29 June 2023 at 4 h 11 min

      Hi Victoria, that’s a good question. I added to the article to explain how to solve the problem of leggy Rozanne geraniums.

  • Jim C. wrote on 4 December 2022 at 18 h 18 min

    Wanted to update this thread and ask for additional help. Over the space of three months, the Rozanne Geranium I bought lost all of her foliage. She went from a lush plant about 12″ in diameter with dozens of pretty purple flowers to one covered by black spots, to one with long, mostly bare horizontal shoots that died very suddenly. I kept cutting away the dead or dying leaves and stems. I hate giving up on my plants. I was reluctant to take your advice Gaspard, because I thought any further shock to the plant would kill it. I was also concerned that I had no warm place in the house to do the wash and transplant. It was below 30 degrees outside.

    However, I eventually realized I had to do something. I found a spot in the garage (about 38 degrees there), and worked very quickly, figuring the thermal shock on the plant would be as bad as the mechanical shock. The root ball was like concrete. I dunked it repeatedly in tepid water to soften it up but finally had to resort to a knife to cut away some of the roots and hard dirt. I never did get the roots fully free of the soil. From what I could see, they weren’t particularly healthy looking. I finally got the plant back into a much smaller pot with potting soil and perlite.

    I brought the plant back inside and then watched to my dismay as every last leaf died. I didn’t know if I dared water the plant, after all the dunking. So I delayed for a couple days. I feared the black spot would come back.. Finally I resorted to prayer. Yes, I pray for my plants’ health just as I pray for my friends and family. and a remarkable thing happened. About 4 days after I saw the last leaf shrivel and die, I saw a couple tiny green sprouts at ground level. I gave the plant a tiny bit of water. In three days it had 6 very slender stems, 6″ tall, each topped by healthy looking leaves! Amazing growth! However I have a new worry. They keep turning towards the window for light, and bending over. I’ve rotated the pot in an attempt to keep the stems straight, but they are now bent in multiple places. The stems haven’t “bulked up” as I hoped, or produced any other leaves. . They are so slender and delicate. I’m afraid they will break.. I decided to insert some bamboo shish-kabob skewers and use some soft yarn to support the stems. However, I wonder if this plant WANTS to fall over and creep like that weed, “Creeping Charlie”. If so, I may have her in too small a pot. What do you think I should do to fill out this plant?

  • Jim C. wrote on 8 November 2022 at 3 h 59 min

    I’m having trouble with a Rozanne Geranium. I hope you can help me. I bought it at a nursery in early September intending to take it to the cemetery. It was beautiful and blooming. A couple leaves had small black spots, which the nursery owner said were normal this time of year. It was root bound. I cut the root ball on the sides and bottom, and put it in a large pot with new potting soil snd perlite. I took it immediately to the cemetery (big mistake), where it immediately got hit with 24 hours rain followed by 24 hours of blistering sun. When I returned it was covered with black spots. I hate to let plants go. I brought the pot inside, hit it with Captan and Immunox. I kept trimming off the infected leaves. After a couple months the black spot disappeared. But the plant is not thriving. It has a small, tight cluster of leaves that never expands. It sends out long (10 – 1 2″ ) shoots that quickly turn brown and die. All the flowers have died. I’m wondering if I didn’t do a good enough job scoring the root ball, or if all the anti-fungal has stunted it’s growth.

    • Gaspard wrote on 8 November 2022 at 4 h 26 min

      Hi Jim, thanks for the thorough walk-through.
      It sounds to me as though your geranium rozanne is set in “bonsai mode”. This happens when it has suffered a lot: the plant reverts to being much more cautious and only very grows very slowly. It’s seen also in trees and saplings that suffer from transplant shock; any good forester will tell you that however well you treat a stunted, one-foot tall sapling that’s already 6 or 7 years old, it will never grow into a tall, beautiful tree.
      However, there is hope in your geranium, because it still tries to send out those shoots. I suspect that it is now in a situation where it doesn’t have enough nutrients to sustain growth, and furthermore, residual anti-fungal products in the soil may keep beneficial fungus from helping the plant out, too. Here’s what I recommend:
      – transplant to a larger pot with fresh soil mix: Gently tease out soil from the root clump, you can even rinse the soil out with rainwater entirely (set the water near the pot for a day beforehand to avoid temperature shock). This will remove excess product which may be poisoning the plant. Afterwards, feed with diluted organic fertilizer, best is the home-made one.
      – alternative path: start cuttings from your geranium. This will give each cutting a fresh start, and it will normally grow much healthier than the now stunted mother plant.
      Of course, you can do both ideas at the same time! Hope this helps!

      • Jim Canale wrote on 8 November 2022 at 6 h 37 min

        Thanks for your fast and very complete answer. Yes, I think you are probably right about the little girl. Too much suffering. Still, surprised that it still sends out long shoots, which promptly die.