cosmos not blooming

Questa, NM(Zone 5b)

I planted plenty of cosmos this year and they're growing full and tall, but I only have a few blooms on a few plants. Can anyone help me figure out what I did wrong? They're in my flower beds where I have other flowers blooming. I didn't add a high nitrogen fertilizer, in fact, for most, I didn't add a fertilizer at all. For some, I laid compost around them.

Thanks!

North Chelmsford, MA(Zone 6b)

It's my experience that they bloom rather late. Next time I'll buy plants.

Questa, NM(Zone 5b)

Oh yeah? I thought this was late. Maybe I'm just imatient. Thanks jean!

Winchester, KY(Zone 6a)

My Cosmos are all from volunteer seedlings, and they've just started getting showy. I've had blooms here and there for several weeks, but now there are several plants with multiple blooms.

I wish I had some of the Sonata series of Cosmos this year (slugs ate all my seedlings), but I highly recommend them if you want to start the Cosmo season off early. They're dwarf, and reach about 2- 2 1/2' tall, with full size blooms and start blooming in 6-8 weeks from seed. I typically start them around May 1 and they're blooming by mid June. Last year I had a few of those reseed, but didn't find any this year.

Questa, NM(Zone 5b)

those darn slugs! They get everything around here.

So your cosmos are just starting to take off? That's good. You're probably a little ahead of me. I guess I really am impatient! That Sonata series sounds wonderful. They must be the ones I see blooming already in this area, because they're short. This year I have Sensation Mix.

Greensboro, NC(Zone 7a)

I usually plant the yellow/orange ones and they are always very late summer through frost bloomers for me here. It's been a while since I've grown the pinks and whites.

Winchester, KY(Zone 6a)

Yep, they've just started looking really showy here. Last year and the year before I got an early start with them and they were looking nice by the end of June, but I noticed those started early also didn't last till frost- they bloomed profusely and then seemed to just dwindle around the end of July. About that time those that showed up as volunteers were just starting to bloom well, so I just yanked out those that were browning. That may have had something to do with the droughts we had in '07 and '08.

I don't know if this is typical, but I've found plants from direct sown seed (or self seeded) seem to have more drought tolerance than transplants. Have any of you had that experience?

Slugs wiped out a bunch of my wintersown seedlings this year- I made the mistake of moving the containers off the deck onto the ground which turned out to be a really bad idea. Ended up with 1 lonely plant of the orange Cosmos, that must have emerged after the onslaught of slugs. Noticed it had its first bloom last week.

The Sonata series has become popular, I'd bet those are what you've been seeing. The seed was pricey the first few years they were on the market, but they're very reasonable nowadays- the best price I've found on them was at Swallowtail Gardens.

Greensboro, NC(Zone 7a)

Maybe successive sowing from spring through mid summer will help with an earlier bloom time and later sowings with blooms lasting into early fall. I've even started cosmos seeds in containers outside in mid July and had 4ft tall flowering plants into Sept/Oct.

Duxbury, MA(Zone 7a)

You know, I was just thinking my cosmos were a little late this year, too. And yet, there's another thread I've been reading about how early people's fall periennials are starting to bloom. My cosmos are always grown from volunteers and I have about 30 plants, and maybe 10 flowers today. When I look back at my photos, the only one I have from previous years is dated July 30 and it's full of flowers. Probably all that rain we had in June, and very little sun.

Winchester, KY(Zone 6a)

Ah, that's interesting. Its been a cooler, wetter summer here too, and I'm seeing several fall plants blooming as well. Several mums and some fall asters are full of blooms now. We have commented that its felt more like fall than summer, the plants seem to think so too!

Greensboro, NC(Zone 7a)

I know our winter temps here are later and milder than they were even 6 years ago. I have some daffodils that pop up in Dec. every year now for 3 or 4 seasons. They're tiny little ones like Minnow but I've got them blooming around Christmas outside in the bed:lol:

Questa, NM(Zone 5b)

I started seeds indoors well before the last frost. The plants are up to my shoulders, they're so big. Just waiting for blooms. I noticed one plant has one blossom. Maybe that's the start of it all.

Summertown, TN(Zone 7a)

My Cosmos "Sensation Mixed" and "Picotee" are just now starting to bloom. Most years, they bloom in mid-June to frost, but it seems the cooler and wetter weather has put them behind their normal bloom cycle. Unlike myself, they do love it hot and dry!

Questa, NM(Zone 5b)

Oh yes! It has been a very cold, wet summer here too. That's another good reason why the cosmos is so slow to bloom. Most everything here has begun flopping and needs staking. I practically need staking for my ground cover! LOL... just kidding.

Thanks!

Emory, TX(Zone 8a)

It is HOT here in Texas, but we've had a lot of rain. The cosmos that I wintersowed has been blooming since spring. But I have several in a bed that came from plants I had last year, and they are all foliage and not a single flower.

Thumbnail by yardqueen1948
Sundance, WY(Zone 3b)

Well, I sure don't feel so bad now. Mine have nothing in the way of blooms yet either. I direct sowed mine late this year, as they went in a new bed I had to get ready. And being much farther north than most of you, no wonder they are so late here. I sure hope they have time to bloom before it snows! Guess if not, I'll start them much earlier next year. Don't know if we'll have warm enough weather for them still this year, as it got down to 40 last night already!

Emory, TX(Zone 8a)

The mystery of mine is the ones I wintersowed are blooming up a storm. The ones that self sowed are the biggest stoutest cosmos I have ever seen, but not a single bud.

Liberty Hill, TX(Zone 8a)

This may have nothing to do with it but a high nitrogen content in the soil can cause beautiful foliage with no flowers, Phosphates (the middle number) make plants bloom you may try adding that. A lot of rain and low temps will cause cosmos to not bloom as they are a heat loving annual.
Lisa

Billingshurst, United Kingdom

Mine are just coming into their own too. This was about 1 week ago from direct sowing in May with young corn plants.
Red orach comes with everything in my garden; like chips ( or fries) but better for you probably.
This one's C. 'Polydor Mixed'

Thumbnail by Mr_Canthus
Duxbury, MA(Zone 7a)

It seems like Lisa's explanation makes the most sense to me. My cosmos are all self-seeded, and although I have some blooms, it's the worst year by far. We had a very cool and wet early summer, and I guess it just wasn't hot enough for them. We did have some hot weather for the past 2 weeks, but yesterday and today are more like fall, so I think I'm going to have to write this summer off for the cosmos. But what's bad for the cosmos is good for the sweet peas, so there's always a silver lining!

Greensboro, NC(Zone 7a)

We had a rainy year so far (still on the edge of drought but the rain helped a lot) and it has been cooler. At least we've had less days this summer with temps over 90 as compared to the last few summers.
My heat loving plants are nice and leafy but not too flowery. During the drought years I even sowed cosmos (orange kind is more late summer friendly imho) in July and had flowers on 3 ft plants in late August/early Sept. That was a very long hot summer though.

Summertown, TN(Zone 7a)

Lisa's explanation does make sense - maybe it is "well-fed foliage"...?

I planted the dwarf "Ladybird Lemon" cosmos seed in a front lawn garden, this spring.
They were slow to come up, but they finally bloomed profusely. Yesterday, though they
were still blooming, I pulled up the plants that were turning brown, and the seeds that
had fallen beneath them earlier in summer are coming up again! Fingers are crossed
for another show!

Lake Toxaway, NC(Zone 7a)

What kind of soil/fertilizer do they need?

Liberty Hill, TX(Zone 8a)

They prefer well-drained soils with little to no fert. They love the sun, heat and should bloom 60-90 days after emergence.
A brief explanation of fert. N (first #) is for foliage, Ph (2nd#) is for roots and blooms, K (3rd#) is for the plant to metabolize the nutrients.
So if I'm not getting blooms I fert. with a product that has a high middle # ie. 6-12-6 and cut back on the water, if possible. Plants usually bloom (reproduce) when they are a little stressed.
Lisa

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