Rosemary Frost Damage

[TromboneAl]

My rosemary went quickly from being healthy to being all black on the lower parts. I'm guessing this is due to the cold temperatures and/or high rainfall amounts we've had recently.

Will it all die? Anything I should do?

Thanks!

 

[Goonie]

My rosemary went quickly from being healthy to being all black on the lower parts. I'm guessing this is due to the cold temperatures and/or high rainfall amounts we've had recently.

Will it all die? Anything I should do?

Thanks!

You can trim out the 'dead' stuff, and see if the plant will rejuvenate. If it wan't killed back all the way to the ground it may very well recover. Otherwise, just sow some more seeds, and if you think it's like to get zapped again, just put some potting mix in a container and sow the seeds in it. If/when there's supposed to be a big temp drop, just carry the container into the house or garage over night. I do that with some herbs, though I've not grown rosemary in years. Good luck!

Or if the tops stay green and don't brown out, just trim out some of the 'dead' stuff and let it go...it might look kinda ugly, but if you're growing it for use then looks aren't real important.

 

[Martha]

Clean out the black stuff, leave anything green. May be fungus or root rot from too much water. Rosemary likes dry. Anyway to dry things out or improve drainage?

Hope you don't have a fungus. Any powdery stuff along with the black?

 

[ladelfina]

Looks more like moisture than cold. Rosemary, like sage, seems to tend to develop less-desirable and more woody sub-sections as it ages. You could use this opportunity for a major pruning-back or at worst re-planting.. and the plants are cheap, right?

On a smaller scale, I see this with our thyme plants, esp. as they get older: the base is nasty, but all the shoots sent out are green at the tip.

 

[Rustic23]

Don't have a clue. Planted some last spring, it didn't make it to the first frost!

 

[FIREd]

I planted some rosemary 3 years ago. It has been through several deep freezes and always pulled through and recovered nicely in the spring. It never looked as bad as the one on the picture though, so I don't think this is frost damage. I am leaning towards root rot. Rosemary likes well drained soil and too much water will hurt the plant.

 

[kyounge1956]

Just as a precaution you might want to cut off some healthy branch tips and see if you can get them to root. Rosemary will I think grow from cuttings, but this is probably not the best time of year to try it. If you have a very sunny window (I forget what part of the country you are in) they might be OK indoors until it warms up outside. If your cuttings take hold you will have fresh new plants that are green all the way down. For a really low-tech option, bend one or more of the branches down to the ground (or if you suspect the soil, a flower pot full of a better growing medium) and put a large rock or brick on top of it. If it roots, fine—if not, then "no harm, no foul".

I am not sure what is making your plant turn black. I have seen rosemary growing just fine here in Seattle, which is nothing if not wet. And when I was a kid, we had a big bush of it in our backyard (in San Jose CA) growing in sticky adobe clay soil. Is it in full sun? That's what it likes.

 

[TromboneAl]

Thanks.

Anyway to dry things out or improve drainage?

Besides moving to Arizona, no. There's no powdery stuff.

It think you're right about too much water. We had rain almost every day for a few weeks (now nothing but sun). It's very shady here and getting more so every year as trees grow.

If the rosemary can't survive in this climate without assistance, I'll have to find something else to grow.

 

[toofrugalformycat]

There's lots of different varieties of rosemary, with different growing requirements. They're cheap, and fun to experiment with. I grow cuttings from fresh rosemary from the grocery store, for example. But I haven't found anything that will survive winter outside up here (or grow as a houseplant for more than a year).