Clip over after flowering. Don't cut too deep. Try not to go into old wood.

Commercial lavender growers in my area suggest a light pruning in fall to remove spent flower stalks and to tidy up the foliage, taking only a inch or so off. And then in spring as new growth becomes apparent, a slightly tighter shearing, removing several inches (but never down into bare or old wood). This helps to keep the plant very dense and compact and reduces the development of the very gnarly, woody interior growth and the tendency to splay open. It also tends to amplify the number of bloom stalks.

Boy, my advise is different. I clip my lavender back to just 5-6 inches in very early spring, as soon as I notice green growth reappearing. In our winters, the plants lose all leaves, of course. Without vigorous pruning, I found the plants would develop an open, spindly woody center. It probably doesn't need to be done every year, but if I didn't make it a habit, it would get forgotten.

Martha

When do lavender typically finish flowering? And you can tell that by when the flowers turn kinda brownish?

What if I want to harvest the lavender? When should I be cutting it then?

That's what I do too, Martha. I used to cut back in the fall, but I have discovered that my lavender fills out more and puts out massive amounts of flowers if I do it in the spring. I was just telling my husband, the other day, how I can't believe how many flowers the lavender has put out this year. And I really think it's a direct result of cutting it back in spring, at the very first sign of waking from dormancy. I think that cut gives it the signal to grow. In researching this last year, I found that cutting it in the fall will send the same signal, at the wrong time, when the plant is supposed to be going to sleep.

Cut each flower when its halfway bloomed. The more flowers you cut, the more will grow. I kept mine flowering well into November by doing this. And I don't think the weather in iowa is all that different from the weather in Ontario so you'll probably get the same result.

Some days I will have a lot of flowers to cut and dry. Some days I'll have one flower, or none. It just depends on if there's any at that halfway point. Make sure you cut at a leaf node and leave a minimum of 2 leaves on the plant. You don't want to cut into anything woody.

Sorry if this is a silly question but what do you mean by halfway bloomed, Jennifer? Do you prune in August?

I also see some of the little flowers have turned brown. Is it time to deadhead?

So sorry for the delayed response! It's been a long, bad week. If you continuously cut, it will continuously bloom. You will get far more flowers from each plant than if you were to just let them them all grow and make one cutting at the end of the season. You can start cutting off flowers right away. And by half bloomed I mean that about half of all the tiny little flower buds that are on the stem, are open with flowers emerging. They don't all open at the same time.