Hibiscus syriacus

clematisdorset · June 2023

My hibiscus syriacus has a few tiny leaves that have recently appeared. I checked the pot it is growing in and the potting mix is very dry. I noticed @Eustace that you might be growing this plant and wondered if I could ask you and anyone else who grows it whether it seems to do better in a slightly dry or slightly damp situation. I am able to move mine from its pot into the ground but became confused with information online because so many websites use different nomenclature. I know mine is definitely hibiscus syriacus and I want to get the soil right! Can anyone help please? Thankyou so much.

Obelixx · June 2023

This is very late to be producing leaves so you need to water it and then feed it. Hibiscus like moist but well-drained soil. Plants in pots are entirley dependent on you for all the water and feed they get as the fertilizer in planting composts last a max of 90 days and there is no access to water.

Give it a good drink now - 5 to 10 litres poured slowly so it can soak in. As the compost is so dry already the water may just drain straight thru without touching the sides so put it in a saucer if you can so it can soak some up and get moist again.

If necessary, re-pot it in a good mix of 7 to 8 parts loam based John Innes no 3 type compost mixed with 2 to 3 part multi purpose compost to help with moisture retention. You'll need to feed it every spring with a good doolop of slow release fertiliser for roses or tomatoes. This will help make healthy foliage and flowers.

Once a week between mid May and mid August, give it a liquid feed of rose or tomato feed diluted according to the instructions.

clematisdorset · June 2023

Thank you very much @Obelixx, that is very helpful. I was a bit stunned to find the soil so dry in its pot, but then remembered I was trying not to keep it too damp after reading various bits of confusing info online. I am going to follow your instructions and write them down in my notes for its care. I hope it flowers this year, but it might not. The weather has been so odd so it really got off to a very slow start. I can plant it out tomorrow into a good potting mix. Thankyou for saving my sanity re this plant!

Obelixx · June 2023

Good luck with it. I had it in my garden in Belgium, in the ground, and it was always late to start cos of the winter cold but then was fine by the end of June.

In this garden in France I have inherited 4 or 5 and the Oiseau Bleu is always ahead, inleaf and flowers, of the others - red, pink and white forms. These are all in well-drained soil but get plenty of winter wet.

I also have the tender tropical version - hibiscus sinensis - which has glossier, darker foliage and vibrant, fiery coloured flowers. They go outside for the summer once night time temps are over 10C.

SYinUSA · June 2023

This type of hibiscus is pretty forgiving and not at all fussy about soil type (in the ground, anyway) as long as it's well-drained. I've never seen it grown in pots, but I suspect it just needed more thorough/frequent watering.

I know what you mean about the different nomenclatures, though. In the US, hibiscus syriacus is called Rose of Sharon. That's quite different than the UK's Rose of Sharon, which is hypericum!

clematisdorset · June 2023

Yes, I am hoping that the leaves were delayed by the exceptionally cold winter @Obelixx and I think the pot was more damp then dry then. I have planted it and the roots look healthy. Mine is Oiseau Bleu, I hope the colour turns out well.

I think I came across H. sinensis as well as 'Rose of Sharon' when I researched online. Even though I knew my plant's name, several websites seemed to mix them all up.

Thanks for your help: I needed someone who grows it to advise me, as many website pages seem to have been written by idiots!

clematisdorset · June 2023

Thankyou @SYinUSA it seems to grow in various climates. I did have an ordinary mallow which was always full of bees. It was not very long lasting though (5 years plus), though it grew quickly.

It is strange how 'Rose of Sharon' gets bandied about to mean various different plants. I remember someone once told me they grew R.O.S. and it wasn't either a Hypericum or a Hibiscus!

Is Hibiscus syriacus a popular plant in your part of the world?

SYinUSA · June 2023

Yes, you see them all over here in Georgia. They are very easy-care and, as I said, unfussy as to soil type, so they are frequently planted en masse in more commercial applications where there isn't a gardener out daily to tend to them. They're just starting to really come into bloom now. Some older varieties tend to reseed rather vigorously, so people generally use one of the hybridized sterile types to keep them in check. I have a couple in my yard, as well as a hibiscus moscheutos.

clematisdorset · June 2023

Oh, interesting @SYinUSA. It sounds like my kind of plant. I bought mine last spring and it did not flower, but I was not expecting it to. This year I think it should flower if the weather plays along. I am going to look up hibiscus moscheutos, and hope there are not 5 different names for it!

clematisdorset · September 2023

I don't think it will flower this year. Maybe it is gathering strength for next year?:

clematisdorset · September 2023

Gardeners' World today had an expert on. According to him, my soil should be ideal. A nice story about how he raised the pale pink Chiffon series.

Hibiscus syriacus

Posts