My Favorite Planting Tips for Iowa
• Take this chance to improve the soil.
You don't have many chances to work the soil deep down. With every planting hole or project, work in a spadeful or a bucketful of compost, depending on the size of the hole. And if you don't have compost (though it's by far superior to anything else), use sphagnum peat moss. I keep a bale on hand just for this very thing and toss in a few handfuls or a spadesful.
• Plant on an overcast day, if possible.
It doesn't matter so much with woody trees and shrubs, but the weather makes all the difference with perennials and annuals, which can wilt much easier. I even like to plant in a light drizzle. My neighbors think I’m crazy, but my plants love it!
• Never plant in extreme heat.
In Iowa, we're lucky that our summers are cool enough that we can plant things much of the summer. But don't plant things when temperatures are regularly hitting the 90s or we're having a dry spell, which in Iowa usually translates into "Don't plant in July or August."
• Plant with caution in fall.
In milder climates, it's fine to plant perennials, roses, shrubs, and trees in the fall, but in Iowa, I feel, it's always a gamble. They're far more likely to do well in spring, when they have several months to establish themselves before winter's worst. If you plant in September or October (except for bulbs, of course), there's a higher risk of their not surviving the winter.
• Root stimulant or no?
I'm a good cheap Iowan and if I have to spend money for it, I'd like to avoid it. I've tried root stimulant and while perhaps it helps, I can't tell a big difference. So I'd just follow good general planting practice (time it right, amend the soil well, keep it well watered for a couple of weeks, etc.) and forget about special additives or chemicals. The exception is if I'm transplanting something a little tricky and it's worth the extra money to me, such as transplanting a larger rose, tree, or shrub.