Susan,

If you are talking about spraying the buds with water like citrus growers do, you have to spray it as temperatures are just hitting freezing so that the water droplets sit on the fruit or buds and freeze, forming a hard shell of ice that insulates the fruit from freezing temperatures. So, unless you're going to stand in your garden with a hose and wait for the magical 32 degrees to arrive, this likely wouldn't be your best option. The citrus growers use their irrigation systems to apply the water at just the precise time it is needed. It is harder for a homeowner to do that unless you leave on a sprinkler all night, which seems rather drastic.

If your indigo bush has been outside and is somewhat hardened off to frost and freezing temperatures, it might be fine with no protection. I have many wildflowers in bloom, including a large patch of bluebonnets, and they handled 28 degrees last week with no damage whatsoever....but they were above-ground ever since they sprouted, some in fall and some in winter or early spring, so the plants themselves were pretty well hardened off, although a lot of the buds had only recently formed.

If you only recently moved your indigo bush outside, can you put a flower pot or some other plastic bucket or container, terra cotta clay pot or sturdy cardboard box over it and use that to support the weight of the blanket? That would allow you to use a blanket of a heavier weight. Even a tomato cage, if well staked so the strong winds won't blow it over, could serve as a support for a blanket.

We have a lot of wind in our forecast with this coming cold front. If you do too, remember to use something to hold the blanket in place overnight. I usually use garden twine and wrap it around the blanket and tie it tightly to keep the blanket from unwrapping itself (with help from the wind). It isn't fun to come outside in the morning and find a frozen plant with a blanket lying on the ground beside it.

Dawn

It has been in the ground for 4 years, but this will be the first year for blooms. I really want to see it bloom. These shrubs are supposedly hardy to zone 2, but that doesn't mean the blooms are impervious to frostbite. I just don't know and a web search didn't tell me anything in this regard. So, I thought that protecting it was the better option.

Thanks, Dawn, I will cover and wrap with twine and hope for the best.

Susan