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Allan designs and plants flowering gardens in Montreal, Zone 5 [USDA Zone 4] .

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Geranium Rozanne:Too Much of a Good Thing

Geranium Rozanne used to be one of my favorite perennials because it blooms floriferously until the first frost, in an intense shade of blue. During the first two years of my garden design business, I included it in every job I undertook because it is a plant that contrasts sublimely against pink perennials and roses. What a mistake that turned out to be! While it does grow lushly in my climate zone, it spreads too far and sprawls in all directions. The clients were not pleased and this year alone, I have had to remove several Rozanne plants from flower beds in which their presence turned neat gardens into messy ones. specs tell us that this plant will grow 20 inches high and that it should be spaced 2 feet apart. Not Quite True!  In my garden, Rozanne had spread to fill a circumference that measured 5 feet in diameter. It also has the power to climb over low growing rose bushes and in that process suffocated some rose branches that ultimately lost their leaves and flowers. growing Rozanne in the garden is like having a guest at one’s table that eats for four people and leaves little food for others. This perennial needs a very wide berth so that it can spread. The only positive consequence of growing such a plant, other than its amazing long-lasting color display, is the suffocation of weeds that occurs in its path.

For Rozanne, it is the stems, and not the root system, that propel horizontal growth. No matter how far the plant spreads, the crown and roots of the perennial remain compact and localized; this is not an invasive plant. If one follows the trail of the sprawling stems that meander through the flower bed, they will always lead back to a compact root ball that is easily transplanted with only temporary trauma.

Rozanne sports an intensely colored flower. Blue in the garden doesn’t get better than this. That is why I was so liberal in using it in the past. However, it is an adventurous perennial that travels messily and that characteristic alone makes it an unwelcome guest in compact flower gardens.

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Reader Comments (8)

I totallly agree with you Allan as I have Rozanne in my garden and trim it back several times during the season. I think this is the answer, whenever we plan Rozanne for someone else we need to advise them not to allow this plant to overtake everything in its path.

I have used Rozanne in plans for several gardens including those for my own children. However, I am able to supervise its growth in my childrens gardens and snip back when required but not in the gardens designed for others..

Your comments have been a good reminder to me to share this advice with the gardens I have designed for others. It needs to be curtailed not omitted. It is still a wonderful plant but obviously needs to be trimmed back every once in a while to be a welcome part of our gardens.

You have said something that needs to be noticed and I don't think I have head anyone mentioning this aspect of Rozanne. I just kind of took it upon myself to curtail its growth rather than get rid of it.


August 9, 2010 | Unregistered CommenterEileen

Allan, I can see why so many people have been taken with Rozanne; that mass of blue flowers is beautiful. The similar geranium 'Brookside' that is popular in this part of Maine flowers somewhat more sparsely and drapes itself over neighboring plants in a more delicate way. I wish I could understand why Rozanne thrives in Montreal but often doesn't survive in Maine. I suppose it could be a question of reliable snow cover, or maybe it has something to do with soil types.

August 9, 2010 | Unregistered CommenterJean

I am amazed at how often plants don't read the garden guide books on how they are supposed to behave! I'm afraid the perennial geraniums I planted did not prosper through my summers, but if they did I would be tempted to plant this one — and give it room to romp!

August 10, 2010 | Unregistered Commenterdebsgarden

Hello from sunny Manitoba in the middle of the Canadian Prairies,

In every garden I plant the Rozanne. From inception, I trim this wandering perennial and so far (XXX) have never had an issue with the stems reaching out too far. You just can't beat the true blue color and I find that as long as you deadhead the spent blooms, this perennial really does provide a show until the first hard frost.

Sad to say that Winnipeg's 2009 November was far too balmy (can you imagine that) for many of my perennials and I lost many of them (25 in total) when the December -30c temperatures hit and no snow coverage. My Rozanne was one of the lost plants. I pouted for a bit in the spring and then as resilient as we gardeners are, I looked at my empty spots as an opportunity to buy more!!

Thanks, Doris

August 10, 2010 | Unregistered CommenterDoris McComb

If there is something next to the mystique shrouds the rose, I think it would be Rozanne. It's a flower veiled in romance and the mystery of love.

September 12, 2010 | Unregistered CommenterCarmel Santos

Does Rozanne grow in S. Florida, zone 10 with high humidity? I would love to have it in my garden, (but will be mindful of your advice!) Thanks!

October 14, 2012 | Unregistered CommenterMoi

Dear Moi,
Geranium Rozanne grows in full sun up to Zone 8. However, mail order nurseries, in an attempt to encourage their customers to experiment, suggest that this perennial will thrive in Zones 9 and 10 as long as it is planted in part shade, [that is, only 6 hours of sun and preferably morning sun] and providing it receives regular irrigation. It's risky.

October 17, 2012 | Registered CommenterAllan

I love my Rozanne and let it bloom away, give it plenty of room and it will drape itself over the stone wall in my garden. It is beautiful.

June 25, 2014 | Unregistered CommenterJane

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