too pretty to deadhead--coneflower conundrum
July 6, 2018 5:52 PM   Subscribe

Local garden center had a sale on coneflowers and black-eyed susans, which are beautifully flowering this time of year. Do I have to wait until fall and/or deadhead them in order to plant them in the garden now?

Located in Central Illinois, which is currently experiencing 90+ degree heat every day. According to the Old Farmer's Almanac, just going ahead and planting these mature, flowering plants in our garden in the heat of summer will kill them. It advises gardeners to cut the plants back to the rosette before transplanting, to help them establish roots.

Is this true? And, if so, is it better to deadhead and plant, or to keep these in their little pots outside in the sun until September or so? They're so beautiful and fragrant right now, and attracting wonderful bees and butterflies, that it's painful to cut them. I guess, if we have to, we can make a nice flower arrangement for inside?

Any advice from seasoned gardeners welcomed. Thanks for your help, green thumbs of the green!
posted by Miss T.Horn to Home & Garden (8 answers total)
Best answer: I have planted blooming coneflower in St. Louis, in the summer, without cutting it back, and it didn't die. I did have to water it a lot to help it get established. I also pretty much only ever plant things in the evening during the worst heat of summer (so the plant has at least several hours of cooler temps to help it recover).
posted by BlueJae at 5:58 PM on July 6, 2018 [1 favorite]

Best answer: Coneflowers in my experience will be fine if you plant them now. They will grow roots. They may be shy the next year and you won't see much, but they come into their own the next.

The are very hardy but they are not like the crazy annuals you buy that flower extravagantly immediately. They take time. They will come back every year and flourish, but they need time.

I love them. Have planted some last summer that the blooms promptly died on. Guess what, they are like a week from blooming now, and I can't wait.
posted by sanka at 6:00 PM on July 6, 2018 [1 favorite]

Best answer: If you plant them now, I'd trim a bit on top but not totally deadhead, and make sure to provide plenty of water.

The thing to remember is that plants need balance on top and bottom. So when transplanting (root damage), it's usually a good idea to compensate for that by removing some green on top, so the water demands don't outstrip water supply. Plants can dehydrate to death even when water is abundant if they don't have the proper surface area of fine roots.

You could also keep them in pots for another month or so, then deadhead and plant, but the thing is you still have to water the heck out of them.

I would ordinarily say planting now is fine, provided you are willing to keep vigilant on watering - you perhaps sacrifice a bit of next year's bloom for fun now.
OTOH the entire region is due for record heat in the next 10 weeks that will probably mess up even well-established perennial clumps, so some extra caution may be warranted.
posted by SaltySalticid at 6:02 PM on July 6, 2018 [2 favorites]

Response by poster: Yes, the record heat is what I'm worried about--not sure whether it would be better to not plant them in this heat or to get them in the ground now, so the roots don't potentially dry out in the pots while we're away for a few days.

What does "trim a bit on top" mean if you're not deadheading? Trim leaves?
posted by Miss T.Horn at 6:13 PM on July 6, 2018

Best answer: What does "trim a bit on top" mean if you're not deadheading? Trim leaves?

You gotta remove something. I'd remove any old/ratty leaves, and leave anything low and small and green. In addition, I'd probably remove a few of the oldest blooms. I'd do both those the day after transplanting.

As for water, and assuming 1-2 gal. pots: You can't leave them in the sun for a few days in this heat with no water. They were being watered daily or more at the garden center. In addition to extreme heat central IL should be fairly breezy right? So that adds more transpiration and water stress.

If you leave them in pots, the best thing to do would be to water them daily. If you can't get someone to water them, you could put them in the shade (under a decent-sized tree), and set them in trays of water (1"-2" deep).

If you plant them now, I'd recommend monitoring closely before assuming they'll be fine for a few days without supplementary water.

Finally: you can rig up a 1-3 day drip-irrigation system by sticking a few pinholes in the bottom of a few 2L bottles and nestling them into the soil.
posted by SaltySalticid at 6:23 PM on July 6, 2018

Oh my goodness do NOT leave them in those little black pots! Plant right away. YES it's hot. YES it's not the best time to plant, but getting them in the cool ground is better than roasting them in nursery pots. Not only will they dry out quickly, but their roots wont have anywhere to go, and swinging back-and-forth from crispy dry to soaking wet stresses and weakens a plant 's immune system. You'll get diseases and bugs.

Plant them, deeply water them in, and then continue to water them in by giving them a good soak 3-4 times a week for two weeks (water early AM). They'll be fine.
posted by missmary6 at 2:50 PM on July 7, 2018

I have transplanted both of these plants mid summer (along with a bunch of other stuff) with no special treatment beyond watering them more frequently. Our front yard had to be dug up for septic and I figured I might as well try and save them. They survived just fine.
posted by Cuke at 3:07 PM on July 7, 2018

Plant them in the ground, do not trim any leaves now because they make the food to grow more roots. If it is going to be hot, cut off the oldest flower heads because they lose a lot of moisture from the plant.
posted by oneirodynia at 5:22 PM on July 7, 2018

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