If the original plants were hybrid seed, it's a simple explanation. Hybrids come from two or more (usually more) different types of plants that have been cross pollinated. For example, there might have been a "mother" that is very tall, a "father" that has a certain bloom size or color, a "grandma" that had exceptional disease resistance. The hybrid inherits all these good traits in one plant. BUT, when the hybrid goes to seed, the progeny are seeds of the mama, daddy, and grandma, individually. This is expressed as "the seed doesn't come true". The only way to get plants just like the hybrid is to buy new hybrid seed each year.

Occasionally, you will see seed advertised as a "selection". This comes from a gardener carefully selecting one kind of plant from a mixture of seeds: maybe a specific bloom color. She removes all the plants from each generation that do not exhibit the trait she is "selecting" and over time, she only gets seed for that one trait. The seed from this plant will come true at an extremely high rate, but you must be careful to cull out the ones that don't if you want to gather and plant your own seed each year and continue to get plants that are alike.

In the past several years, I have noticed that alot of bedding plants I get from Wal-Mart turn out to not be uniform in size or habit. It is my suspicion that in order to give us the absolute lowest price, they are collecting and using seed from hybrids. I have become very careful to only buy plants from them that have tags for named varieties. The last year before I did this, I had a bed of melampodium that ranged from 8 inches high all the way to eighteen inches high. Needless to say, the queen was not pleased. :)

Thanks. That's happened a couple times to me too (from plants I bought from nurseries).

Hi cookie8! I know that some plants, cosmos included, do not like the soil to be too rich or fertilized. They will grow very healthy and produce lots of foliage, but very few flowers. I find that the more neglect with cosmos, the better, along with things like nasturtiums and probably blak eyed susans too since I am great at neglect and my BES to great. With your BES, it could also be the fact that since they are perennial, they were just settling in and getting established as perennials need to do......'first year they sleep, second year they creep, third year they leap'. You just never know! :)
gg

Out of over 50 Cosmos seedlings there's ONE the deer/rabbits/groundhogs haven't eaten. I'm furious.

Send me a wacky one...I'd be glad to have it...LOL.

My home collected seeds have some of the same problems-
My cosmic cosmos ( dwarf) has crossed with another that is orange and yellow but tall 'Bright lights'= all the seedlings are now orange and tall

If I want a dwarf I guess I will have to buy seed again.

Same thing with Delphinium 'blue butterfly' (dwarf) It must have crossed with my 'Pacific giants' = all my seedlings are 3 ft tall but bushy like blue butterfly
If I want the dwarf form ( I do!) I will have to buy it I guess... hmm...

I'm guessing the dwarf forms can't compete with taller ones for resources or are recessive genes- as the grandchildren are full size.

If you have managed to produce a dwarf form- you should contact a seed company- they like dwarf varieties as the consumer is likely to buy them with a smaller garden these days. Also don't share with anyone. Thompson Morgan and Wayside/ Parks want to be exclusive.

I did when I had a variegated datura. I would recommend Proven Winners
Thompson Morgan, and Wayside/ Parks. All 3 responded with interest to my emails. My plant is now at Proven Winners/ Amerinova. It has been there for 2 years now... I would also recommend Plant delights because Tony was insightful altho not interested.

Contact me directly if you need more info- it has been a learning experience.

Karen

One of my Cosmos plants is 19 inches tall, how much taller will it have to get before it blooms? They are mixed Bright Lights.