for me.. in z5 MI ... sounds like 4 oclocks would work ... they are really slow to get going.. from seed in spring.. due to cold soil ... and really dont start blooming until August some time...

but alas poor yorrick ... i dont know the timing aspect for your backyard ...

ken

I don't think that I've ever had my dianthus turn brown on me. The spent flowers look terrible, but they can be snipped off in a jiffy. I love the blue foliage of dianthus and would be pretty bummed if the whole plant browned out.

What about planting an annual that would grow to cover the dianthus by mid-summer? I'm picturing zinnias, which I love for their ability to attract butterflies and other insects.

Martha

What about Sweet William 'Wee Willie'?

thanks all. yeah, zinnia is an idea.
I'm planning to plant them anyway. Last year they were the stars of the garden, and attracted loads of butterflies.

Lobularia (Sweet Alyssum) is a good option. It will grow in the same type of conditions as dianthus and maxes out at about 8-inches & blooms through late summer to early fall and it smells heavenly!

Here is a link that might be useful: Lobularia (Sweet Alyssum)

Hmmm...I think of Lobularia as a cool season plant.....like many members of the Brassicaceae family.

Yeah, lobularia looks pretty sad in July or August here.

You could try vinca (Cataranthus). It comes in lots of sizes from nearly two feet to six inches. Pick the size that works for you. It's about the most foolproof and reliable annual in the Deep South zone 7. (It's helpful if you always include your state when you post.)
Some others that would also do well would be Serena or Serenita Angelonia; Zahara, Magellan, or Profusion Zinnias; Victoria Salvia, Gomphrena, or even lantana. All of these will bloom their heads off in the highest heat of my summer here. If your bloom season is very long like mine (April to November), you'll want to give them all a good cutback in mid summer to keep them looking their best into fall.