Why annuals opt out as summer settles in

When annual flowers are perennially troubled, switch species

I don't know if you remember, but last year I asked about healthy impatiens wilting and dying in mid-summer.

(We do remember, Wendy. You wrote, "I love impatiens. and most of the plants thrive. However, every year, a few of them seem to shrivel and die. The leaves get smaller and the stems seem to shrivel." We told you about Alternaria, Botrytis and other fungi that can invade damaged stems and crowns to become chronic infections, and which may already be present in some plants at purchase.)

You did some research and found some information about a blight that is in the plants before we get them. And I thought that was it! So, this summer, all seemed to be going well until July when the odd plant here and there started in with the dying. And one plant spread to the next plant so I started pulling the dying and replanting. Those replacement plants did well here into September.

Two things I've noticed:

  1. Impatiens in front of the house (west facing and primarily shaded by a tree) have had no sign of this blight and are doing well.
  2. The bed with the blight is east facing and the impatiens that die seem to be in more sun at the end of the bed rather than in the more shaded end of the bed. BUT - not all the plants in the sunnier end die.

So, do you think it's in the soil? Or is it the sun? If it's in the soil, should I remove some of the soil and replace with new? Can I treat the soil with something? I did spray with some lime sulphur in the early spring thinking that would kill whatever blight might be lingering from last year.

Thanks for any thoughts

- Wendy -

We're glad you wrote again, Wendy. "What happens next" is vital info. We apologize that our last exchange created the impression that the problem was definitely that the plants started out blighted. We commend you for putting yourself onto the right track which is looking at the bigger picture. When it comes to recurring- and whole-bed problems, that's where answers lie. In this case, we see a whole species painting out a pattern that says, "We Impatiens don't want to be here."

What we should have emphasized is that agents like fungi that enter through wounded or cold-injured stems are not the real killers. Stresses that makes a plant too weak to grow past or fight off such agents are the problem. When a problem persists after you eliminate all stress factors under your control -- by handling plants gently, loosening subsoil along bed edges pressed by wayward feet and tires in winter, not planting until the soil is warm, etc. -- then it's time to give that plant species a break.

Impatiens love cool, partial shade. That individual plants manage to keep going in your garden or anyone else's even after their kin succumb to heat doesn't change that overall preference. That replacements planted after July survive seem an additional proof that midsummer heat was the last straw.

So, Wendy, look into other species this winter. Grow plants there that are more heat-tolerant. One to consider is Catharanthus (called annual periwinkle).


Sometimes just one step back, and one brief period of early winter rest and mid-winter wonder time, lets the patterns we see in the garden speak to us. - Janet -