Protecting Rosemary from Winter

Asked July 22, 2016, 7:44 AM EDT

Hi - I have a good sized Rosemary plant in a protected area of my garden. Last year I lost alot of it due to winter freeze - it came back nicely but I don't want to lose her this winter. It's very healthy now and I want to keep her as long as I can. Should I wrap it this winter in order to protect? and if so with what? I see conflicting information on the web. Thank You,

Prince George's County Maryland

5 Responses

We have really had some rough winters in the last couple of years.
Taking precautions to protect beloved semi-hardy plants are not a bad idea.
There is no hard and fast rule about how to do this, so you have several options.
One is to stake burlap around the plant. You could increase the protections by stuffing straw or fallen leaves around the plant. Avoid big, thick leaves already wet and matted together, and check it a couple of times during the winter to make sure that wet clumped leaves are not sitting on the crown of the plant.
If you are ok with the look, some people just pile bagged leaves on top and around the plant.
Another option is to find the thickest grade of floating row cover you can and make a barrier tent with that.
cm

We have really had some rough winters in the last couple of years.
Taking precautions to protect beloved semi-hardy plants are not a bad idea.
There is no hard and fast rule about how to do this, so you have several options.
One is to stake burlap around the plant. You could increase the protections by stuffing straw or fallen leaves around the plant. Avoid big, thick leaves already wet and matted together, and check it a couple of times during the winter to make sure that wet clumped leaves are not sitting on the crown of the plant.
If you are ok with the look, some people just pile bagged leaves on top and around the plant.
Another option is to find the thickest grade of floating row cover you can and make a barrier tent with that.

Super - thank you - I guess anything would help..... it's about 4 feet tall and wide, so I may opt for the tent or build a small structure around it and fill with straw.

another question - unrelated..... I went to divide my iris' this morning and horrors!!!! they all had bore-ers and rot - so I had to throw it ll away - heartbroken.

However I have other iris beds to clean out that from the surface don't seem so sick..... is there prevention (aside from cleaning and sanitation) I can use to protect my other beds? something to kill the borers left in the soil? do I need to decontaminate the current borer-infested bed to make sure I can put healthy iris back in there?

Thanks

Iris borers are the most serious pest of iris, but don't worry, they are more than manageable. Knowing their life cycle helps with control, and the plants themselves are pretty tough. It's not usually necessary to discard whole plantings, but just cut out diseased, rotting portions (a bacterial rot often follows their chewing) and let them totally dry, or dust them with sulfur and replant.
Caterpillars of this pest hatch in April/May when the leaves are about 6 inches tall. They climb the young leaves and drill into them (pinpoint size holes) and feed going downward. The trails look like leafminer feeding. If you notice this, you can just pinch the leaf at the lowest point and slide upwards, crushing the caterpillar within the leaf fold.
By this time of year, they have bored down to the rhizome and have been happily feeding and hollowing out/causing disease. Some books suggest there is only one borer per rhizome. Any you see should be squished.
Once they finish eating, they pupate in the soil, and the adult moths fly at night and lay eggs on foliage and debris at the base of the plants.
It is suggested that a good fall cleanup is helpful. You can cut the flower stalks and leaves at the base, clean up any dead leaves etc. nearby and get them out of the yard.
Some gardeners have good effect with removing any damaged or diseased leaves whenever they see them.

cm

Regarding rosemary, I'd like to add that tender plants will always benefit from mulch to protect roots so at least do that, and if do fence, be sure to stuff the mulch under the lowest branches. Secondly, additional protection is provided by locations next to buildings/walls and near other heat absorbing material such as concrete and asphalt. Finally, some varieties are known to be hardier than others, so if need to replant, choose one of those. Back in the day, the best were Arp and Hill Hardy (sometimes appearing as Hardy Hill), but there are probably others (and better) now. Note also that I have lost both cultivars in Severna Park, planted in front of a west facing chimney. A gardener's life is always a challenge.
Good luck from an AA Co gardener