Geranium Yeoi (syn. Geranium rubescens) at OpdeHaar gardens

Geranium yeoi

Op this page about Geranium yeoi there is information on and photos of:

Geranium robertianum / Geranium maderense/ Geranium Yeoi 

Geranium robertianum or “Herb Robert” is well known in northern Europe where it generally has the status of an attractive weed. We never saw it in our woodland until more than 20 years ago when Joyce found a small seedling on a path during a walk on Madeira and decided she would grow what we had decided was a seedling Geranium maderense. It turned out that we had not saved the largest member of the Herb Robert family but its baby brother which is perfectly winter-hardy here in the Netherlands. It now appears literally everywhere around our property. I find it a decorative little thing and only move it when it is definitely in the wrong place; this is very easy to do and is not a chore.

We have subsequently grown G.maderense in pots – seed is widely available and germinates readily. This giant Herb Robert is a short-lived plant which is usually treated as a biennial but is not a hardy plant outdoors in The Netherlands. It is the largest Geranium and I have to confess that I find it the most attractive. Ironically, if you travel south east from Madeira to The Canary Islands, just off the coast from the Sahara desert, you arrive at the home of another Herb Robert in the form of Geranium palmatum. This is arguably rather less spectacular than its northern cousin but is reportedly more winter-hardy back home in NL. For readers wanting to delve into more practical background detail on these two geraniums, there is a really informative blog by Dan Cooper who gardens in Kent .

In a garden such as Op de Haar cared for by a couple who aren’t getting any younger, any plant which demands the care of a container year-round has to be exceptionally special to be added to the collection. A couple of years ago, I could hardly believe my eyes when I saw a tray of what looked like G.maderense at our local nursery run by a real plantsman couple, Hans and Miranda Kramer , which on closer inspection was named as Geranium yeoi which the literature reveals to be a re-naming of Geranium rubescens . The photo and text taken from the Hessenhof website are both informative and revealing:

Hans says: “According to the literature, this Madeiran native is biennial but this is definitely not our experience. Moreover, although it is a relative of our Herb Robert, the flowers are five times larger and fluorescent magenta-pink and we have recorded a size of 4.5 cm. The plant itself is highly reminiscent of Geranium maderense” . Hans goes on to speculate that maybe the plant he has is maybe a hybrid with something like G.canariense ( now G.reuteri) with a far higher degree of winter-hardiness than previously realised. The photo below of plants at the end of the first growing season in our garden gives an idea of the size and the foliage :

Seedlings

Whatever this mystery Herb Robert is, it does provide seed because I discovered seedlings in pots under the greenhouse staging after a plant I had there flowered. It should be noted that Hans has a VERY free-draining soil at his nursery which invariably helps plants of marginal hardiness through the winter. My first plant which over-wintered in 2017-18 seemed to want to continue growing and flowering through what was a very mild winter. There was a sudden very cold period at the end of March (“Beast from the East” as the media christened it) and my plant rotted off at the base. This prompts me to remind people growing both G.yeoi and maderense that their lower leaf stems (petioles) get very wooden and seem to dry off. The last thing you should do is try to neaten up plants by trimming these stems off because they support the plant which has a rather weak root structure and stop it flopping over on its side. (G.palmatum is not reliant on this ancilliary petiole support mechanism)

The winter of 2018/2019 was neither cold nor wet here in the central Netherlands but the gardener in me triumphed over the scientist and I put bubble plastic covers over my large geraniums until the start of April. As I write these lines on 1 June 2019, both G.palmatum and G.yeoi  have been in flower for 3 days or so and both have very similar flowering stem structures with the significant difference in plant size being the only visual difference.

The larger geranium variety (G. yeoi) lacks any hint of red pigmentation in its stems which adds weight to Hans Kramer’s suggestion that it isn’t actually G.yeoi/rubescens. While its size and the support mechanism of resting on lower stems are shared with G.maderense, this is where similarities end. This line of thought prompts one to wonder if indeed it is a hybrid involving G.maderense with one or more other exotic Herb Roberts such as G.palmatum and even G.yeoi/rubescens itself. Besides continuing to monitor the perennial nature of my plant, I need to cultivate the genuine Geranium yeoi so I can make more informed observations. The saga continues!

Seeds

Towards the end of June 1919, I removed the flower stems from four geraniums I had planted early in 2018 and harvested a large quantity of seed and immediately surface sowed a portion in a seed tray. Germination was quick within a couple of weeks and as good as 100%. Seedlings developed rapidly and were soon ready for potting on and by September were large enough to be planted out in a range of locations around the woodland garden. The idea is to see how they respond to a range of varying shade and moisture levels besides monitoring their hardiness and longevity. Importantly, I should note that as far as I can see, the plants are identical to their parents.

Winter hardiness

The 4 mother plants came through the very mild 2019/2020 winter without any protection and have become almost sub-shrubs of about 1 metre height and circumference. In fact, this size really does need allowing for when positioning a new plant . These established plants are flowering more abundantly than ever as I write in mid-June. Their progeny around the wood are clearly putting their efforts into growth and have fewer flowers but seem very tolerant of shade and, indeed, the dry conditions we had in the Spring.

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