Daily Flower Candy: Convolvulus sabatius

Mention the name bindweed and the first thing that springs to mind is one of gardeners’ greatest horrors, hedge bindweed (Calystegia sepium). Undoubtedly beautiful in flower, hedge bindweed is a thug and is welcomed only into the wildest of gardens by the bravest of gardeners.

Altogether tamer, docile in fact, is blue rock bindweed, Convolvulus sabatius (also known as C. mauritanicus). An extremely polite customer, this small, scrambling plant stays in one place, flooding the ground around it with pools of delicately creased blue flowers. They start to unfurl at the end of May and often persist until November. I have grown Convolvulus sabatius in our coastal garden for many years now, giving each plant a haircut in autumn and then again in April. The trailing stems, cascading down our slate walls, tend to get tossed about like a bad comb-over during winter, so a trim keeps the plants tidy.

Convolvulus sabatius, The Watch House, June 2015

In the UK Convolvulus sabatius is commonly sold as a annual for hanging baskets and containers. This is often the cheapest way to obtain plants, but in the south of England you will find them perfectly hardy and reliable as perennials. Blue rock bindweed does not wander or set seed, simply making a stronger clump year after year. For best results plant somewhere that enjoys sunshine for at least half the day. Positioning at the top of a wall or slope gives the trailing stems a chance to show themselves off. Once established Convolvulus sabatius needs almost no maintenance and is very drought tolerant. If it does outgrow its allotted space then I give it a haircut and new shoots quickly appear – in a good season I might do this a couple of times. The flowers close in the evening and when they’re over they roll themselves up into tight twists like little Rizla papers before dropping. Their colour is an exceptionally pretty mauvish-blue, which works well with hotter pinks and yellows.

With its lens-shutter flowers and good manners Convolvulus sabatius is a bindweed I could never banish to the fringes of my garden.

Convolvulus sabatius, The Watch House, June 2015

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12 thoughts on “Daily Flower Candy: Convolvulus sabatius

  1. I love your posts and your gardens. Thanks for your newsletter.

    I am looking for a colorful climbing plant for a shady area – any ideas other than clematis?

    Best, Patty Crowe USA

    Liked by 1 person

    1. How about Hydrangea petiolaris, or better still Hydrangea seemanii? I am growing Trachelospermum jasminoides and Holboellia latifolia in a degree of shade – both lovely but not as showy as clematis. Hope that was some help. Dan

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  2. Thank you for the insight. I’ve not grown it before, but wanted something different for one of my large terracotta pots this year. I’d assumed it what as annual (fooled by the name C. mauritanicus) but at the end of the summer I’ll rescue the plants from the pots, over winter and find them a new home in the garden somewhere. I’m sure that they’ll do well here if I can tick them into one of my dry stone walls.

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  3. Frustrated gardener I wish I could persuade you to come and live in the wet tropics, your insight and aesthetics would be very welcome.

    Of course I’ve tried Convolvulus sabatius, who wouldn’t, I can feint with joy looking at it in full bloom.

    It started failing within a week of planting in rampant, heavy, steamy, humid monsoon rain, then still just gasping for life a violent typhoon battered and shook it to death. As always I was shocked to the core. A week of dreaming gone, dissipated up in the clouds.

    I got it in Australia while visiting far less challenged gardener relatives living in Tasmania, the gateway to Antarctica. In fact the wonderfully designed Antarctic Science Research & Development building’s lovely stone walls are dripping in the stuff. There it seems happily rather rampant, softly covering vast ramparts of artfully laid stone in ultramarine, rooting as it goes.

    I never give up trying, we are in desperate need of those hanging plants that can be made to behave while smothered in mesmerising colour in the tropics. It was all so easy in London, yes winter always threw me into a foul deep depression but nothing that a few weeks gardening in Andalusia couldn’t fix, here Im surrounded by tropics for thousands of miles every direction.

    I have thirty or so very large dark glazed antique Chinese dragon pots desperate for hanging jewels. Colour colour colour!!!??? Sigh. Coarse rampant foliage plants in three hues just dont do it for me in quite the same way as true blue and purple does.

    My guiding light, the rather unfortunately named Karvinski’s anus. Yes this delicate fairy wall hanger daisy Erigeron karvinskianus thrives in the tropics, who would’ve thought. I brought a pot clumsily ripped from my beach cottage in South Africa where it makes the broad stone steps leading to the sea a thing of magic. It took off here, in fact it’s become a nuisance. It also never flowers like it does elsewhere in the world but grows and grows instead, a weedy feathery ground smotherer. But yes at least it grows! In the very depth of our dry season amongst the intense and glorious bougainvillaea gasping for blue it’s peppered with a sprinkle of absolutely forgettable colour, but those lovely little flowers just serve to remind me why it’s there. That’s enough for me.

    You can see how much we need you.

    I have my sights on the fabulously named and fabulous looking creeper “Jacquemontia violacea” now a rather bland “pentanthos” I believe. I saw it growing so well up a fence in Bangaluru last week just behind a grove of coconut palms. I just have to get me some. It’s not well behaved but I don’t mind quite honestly if I drown in true blue. Unfortunately there was no seed in sight at the time and the gardeners were untouchables which made conversation sadly extremely difficut as they shrank from view when ever I approached, vanishing into the confusing dark palm trunks like spirits. I even tried learning Hindi and bearing gifts but to no avail. It’s proving difficult to find seed but Im on it…

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    1. I love the look of your elusive jacquemontia Anton. If you are craving blue have you thought about Thunbergia grandiflora or T. laurifolia which are of Indian origin? I will be in India myself shortly, although restricted to Delhi I expect. Fascinated to hear that the erigeron tolerates the wet tropics. It enjoys no such conditions in our London garden where we are trying to get it to colonise the cracks in the paving. Have a lovely weekend. Dan

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  4. Yes!!! Seeds of Jacquemontia pentanthos are winging their way to me as I type, least I hope they are. I never know with the internet. I’ve paid for them and received confirmation from Paypal that I’ve paid for them but nothing from Sunnyside Up (or something like that) the seed merchant in Florida. Im a bit worried because they seem to mostly specialise in what they call “heirloom” tomatoes which is a very different thing I imagine, something I don’t even understand. Maybe made into “artisan” tomato chutney or something….no idea. Anyway there they were only 5$ a packet!?

    Thanks Frustrated I have indeed tried and indeed still have Thunbergia grandiflora, will always have T. grandiflora. Once tried you’re never without it. At the moment it’s hanging its truly lovely long flower trusses spinning its powder blue flowers down from the top of sixty foot camphor trees in the forest surrounding my house and garden while simultaneously strangling a giant bamboo and reaching out to try and smother everything else. It escaped! Weekends we spend hacking it back and away from the garden. The odd recklessly tossed pruning (and there are many) easily root and grow where they land in our 80% humidity and 33%C temps. It also produces enormous tubers deep under ground as thick as your thighs with a texture of a carrot, resisting all attempts at eradication. Maybe good for improving clay soils. Chop slice and dice all you want you will just get wet, dripping wet from head to toe and every piece of fractured tuber left will happily start sending up triffid like tendrils.
    I love the form and colour of the trusses of flowers but its not something I would wish on my worst enemy. I think up there with Japanese knot weed. This is not the blue I happily drown in. It does flower for a long time even if most of the flowers with the slightest disturbance end up a messy squidge on the floor, the trusses just grow longer and longer. However for most of the year it looks like a cucumber vine on steroids. I would say almost impossible to keep in check. Forget it for a couple of weeks and you’re lost. Im almost sure most people give up after one or two seasons no matter how prettily you originally managed to hang it from that pergola. It’s one of those plants that IMO at least truly and utterly defies any attempt at domestication no matter how grandiose your vision might have originaly have been.

    Im putting all my faith in Jacquemontia, it’s a completely different creature. The vine is light and delicate, spreads in a more timid manner and not terribly far either. Im just hoping its roots will be OK with our rainfall which can be very very high. The fact it flowers mostly in the dry season is a big plus.

    India is lovely hope you have a good time. I would definitely like to go back and do other parts of Kerala where we drove to from our arrival in Bangaluru. I brought back bags and bags of Hibiscus cuttings and a truly stunning chartreuse coloured Holmskioldia sanguinea. I only have the red one so was delighted to find it growing wild along an elephant ditch, the ditches villagers dig to keep marrauding elephants out. Locals are very generous and elephants are very clever, they had bulldosed the ditch in at just the right point for the villagers to reach the shrub on the other side. They had their machetes out hacking a path to find me suitable material in no time. Im delighted to say just a week back and they’ve already rooted.

    Have a good time.

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  5. I have one of these trailing from my bathroom cabinet (south facing bathroom) but recently the leaves started to turn yellow and I am concerned it may not survive as an indoor plant. Any advice?

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  6. All my Jacquemontia pentanthos seed that i bought on the internet from the USA were duds, not one of the tiny seeds germinated. I was very disappointed and postage included rather angry at throwing away 50US$. Luckily I managed to get a plant in Sri Lanka, last minute, two weeks ago. On my last day I found a nursery near my lodgings that had a number of rooted cuttings! Damn heavy thing it was, soggy grow bag full of hardpan clay. Anyway it took to the air like a duck to water and made the five hour flight in excellent shape.

    Its rambling up my fencing with remarkable speed breaking out in leaf bud all over the place. Already survived one full no 8 typhoon assault no problem, so things are looking good.

    It is quite remarkable how similar the flowers are to Convolvulus sabatius, except in little clusters of ever renewing buds which i hope to see plenty of in our dry season.

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