I trim mine off right to the ground in the spring and let them grow back. I just fertilize with what ever I'm using on the whole bed.

I think they like a more alkaline soil than ours, so I give mine some lime.

They really thrive in the alkaline soils I've lived on--don't know if they need it, though.

Yeah, clip them down in the spring if you want. I've never bothered to fertilize--they seem to do just fine without--doubling in spread every year. I love dianthus!

They are like lilacs in that they are one of the plants happier with a moderately alkaline soil.

Great. So if I want to add lime what do I use?

Poorbutroserich,

There is limestone bedrock in the Nashville area. You might want to research whether you need lime or already have it. Too much of anything can cause problems.

Cath

Cath, I believe I am on granite. I have floppy pinks...Would fish emulsion help?
Thanks

Susan

Susan,

I am no expert on pinks as very few grow well on my (albeit alkaline) clay. The only two I have seen thrive here were an unnamed one, identified here as Rose de Mai, and Neon.

Cath

What sort of dianthus? As a rule, they don't need lime unless you have acid soil (in which case, there are better choices than dianthus). More important than ph, I think, is getting the watering right - they hate sitting in wet soil. As for cutting them back, depends on the type.

Dang Camps! I knew you were going to force me to get out the Latin. I am unable to italicize so forgive me. They are the allwoodii and similar. Clove scented. The old fashioned ones. Inchmery comes to mind. Not plumarius. Is that helpful?
My ph is close enough to neutral that I consider it neutral. I think humidity is more my problem. How can I find gravelly grit to improve drainage?
Cath, Rose du Mai does well for me too.
Susan

If you want "gravelly grit to improve drainage" but don't want something which will "lime up" the soil, look for aquarium gravel -- the cheapest you can find. Otherwise, do the vinegar test on anything else -- if a few drops on the rocks makes things fizzle, then there's limestone in the rocks.

:-)

~Christopher

I was going to suggest chicken grit - far, far cheaper than alpine grits or other horticultural grits.....and you can get the mixture of flint and oyster shell which dianthus love.

Dianthus X Allwoodii pinks - yep, you can snip out the old ratty looking stuff - take out the entire old flowering stem - there will be new growth at the bases of each clump....and try to keep up the deadheading - these old pinks used to be once flowering but many of the Allwoodii types (most famously, Doris....and Inchmery of course) will flower in flushes thoughout the season.
Interestingly, the Allwood family gardened on clay - took years of amendment, but anything is possible, right?
Don't forget to take some cuttings mid season (pipings) nothing easier than popping a few stems around the edges of a terracotta pot with a nice gritty mix. Guaranteed success.

Dang Camps! You read my mind! I've been researching dianthus propagation. You make it much simpler than the books.
Aquarium gravel and chicken grit. Sounds great. Christopher we should swap some!
As always, thanks!
Susan

Susan, that could be a possibility -- in a year or two. I have a few coming in a couple weeks, but remember that I'm just starting this garden. The beds were made and planted last year with just roses, and this year will be the companions. As far as Dianthus, I have the following coming:

'Bath's Pink'
'Fire Witch'
'Greystone'
'Inchmery'
'Jan Louise'
"Mom's Cinnamon Pink"
'Mrs. Sinkins'
"Old Vermont"
'Raspberry Surprise'
'Rose de Mai'

My plan was to use the Dianthus at the front of the log edging, alternating with some sprawling Sedums and various blue- or purple-flowered "others" (Lithodora, a couple Veronica, a couple Campanula, etc.) . I was thinking that planting them high in the raised beds would give them the drainage they prefer. I'll have to remember to get some garden lime or crushed oyster shells to sprinkle around them. I wonder if I could just bury a whole oyster shell under the roots -- I work in a restaurant and have easy access to them.

:-)

~Christopher