Liatris spicata and pycnostachya difference?

dkkbeach(VA)

Hello! I grow Liatris spicata and I noticed that some were different than the others; the others having purple stems right below where the flowers start. I was trying to find if it was another specie and I came across L. pycnostachya which looked extremly similar. I couldn't see any difference but the book said it had "reflexed, long-tipped involucral bracts." I have no idea what that means.... Could someone help me out please. I hate having miss-labled plants! btw: I planted half from seed and some from a bag of bulbs both labled Liatris spicata. Thanks for reading. ~David

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Judy_B_ON(Ontario 5B)

They do look very similar. The bracts are tiny green leaf like bits on the base of the individual flowers (not the tall spike, the actual flowers in the spike). They remind me of the bits on an artichoke that you tear off and eat. You will need a magnifying glass to look closely. Reflexed means that the bracts lean or tip backwards.

The various liatris hybridize quite freely so if you got the seed in a trade from another gardener it could be either plant or a hybrid. I grow four different kinds of liatris and I would never consider the seed or self sowed seedling plants from any of them to be true to the parent plant.

Here is a link that might be useful: Liatris Pictures

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dkkbeach(VA)

Wow, thank you. I see what you mean. They are just like fish scales. I checked all mine and they are definatly L. spicata. I guess some of them have a different color because they came from different places. Thanks for the clarification. :)

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paalexan(NM)

Clarification of the clarification (since I'm anal): the involucral bracts (also called "phyllaries") occur at the base of the flower heads, not at the base of individual flowers (of which there are generally at least a half-dozen per head in Liatris, up to hundreds in other things in the aster family, like sunflowers). They are indeed exactly the same structure as the bits you pull off of artichokes.

Patrick Alexander

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john_mo(z5/6)

I am not so familiar with the technical differences in the flowers of these two species, but here is how I generally tell them apart:

1. Spicata is shorter, typically about two feet. Pycno gets much taller -- often over four feet.

2. The leaves in spicata extend up the stem such that leaves are interspersed with the flowers at the bottom of the flower array, giving the plant a 'spiky' appearance. The leaves of pycno are more exclusively basal, with no prominent leaves in the portion of the stem where the flowers occur.

I don't think the differences in stem color are diagnostic. I have seen individual plants of Liatris spp. that have reddish stems, while surrounding plants (same species) do not.

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paalexan(NM)

Well, I haven't seen Liatris pycnostachya, but the Liatris spicata I've seen in Indiana were generally around 4 feet high, so I don't think height is always going to work.

Patrick Alexander

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Soeur(z6b TN)

Yeah, the L. spicata I've seen in the wild here in TN is easily 3-4 ft tall. It's one of the taller species around here, L. aspera being the big daddy at 6 ft or so.

Soeur

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john_mo(z5/6)

It's possible that my L. spicata are a cultivar, some of which are selected for short stature for convenience in the garden. I do think that the difference in the extent of leaves up into the flower stalk may be a more reliable difference between the two species.

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paalexan(NM)

To be honest, I'm not too sure what you're referring to when it comes to the leaves. In the process of dinking around a bit online... the impression I'm getting is that how obvious the bracts in the lower part of the inflorescence are is dependent mostly on how far down the inflorescence flowering has progressed. For instance, in the pictures of Liatris pycnostachya on this page and the second picture down of Liatris spicata on this page, the bracts are fairly obvious in both inflorescences when the lower flowers haven't opened yet. On the other hand, in the top picture of Liatris pycnostachya on this page and in the top picture of Liatris spicata on this page, the lower bracts are inconspicuous on both species once those lower flowers have opened. On the other hand, the differences in phyllaries shown on those pages are fairly obvious...

Patrick Alexander

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william_illinois(z5 IL)

My experience with these two species is that Liatris pycnostachya is taller than Liatris spicata in the same growing conditions, but the heights are variable enough to make height a very poor identifying characteristic. The reflexed bracts on the individual flower heads of Liatris pycnostachya (giving the flower heads a bur-like appearance) are obvious close up. When the plant is done blooming the same reflexed bracts are obvious on the dried seed heads.

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john_mo(z5/6)

Sounds like you will need to use the differences in the bracts to make a sure identification. My description of the differences in general appearance doesn't seem to be reliable, based on photos I have Googled. Around here, pycnostachya is the common wild species and it is usually very tall. In contrast, spicata is popular in gardens and (I think) the shorter cultivars are most commonly planted. This makes the difference in general appearance more pronounced than it is between the wild species. Sorry if I led you down a wrong path.

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bluesgarden(7/8)

I need info. I bought 200 Liatris spicata "bulbs". They looked like small brown rocks, . I planted them here and there to fill in some areas of my beds. I have yet to see a single sprout. It has been three weeks or more since I planetd them. Any one know how long they take to show themselves?

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kwoods(Cold z7 Long Is)

My established liatris of varied species (including spicata) are just now peeking their heads up. I find they like to be pretty shallow in my sandy soil. Patience, the ground is still warming and yours are new.

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bluesgarden(7/8)

Thank you kwoods. The day I posted my concern I went out and there they are. I am tickled.

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ahughes798(z5 IL)

William, bingo..I find that the blooms on the L. Pycnostachya look a lot different than the on L. Spicata.

The blooms on the LP look more like the blooms on a L. Ligulystylis than they look like the blooms on an L. Spicata.

I grow both of those, and L. Ligulystylis(sp), too. However, the L. Ligulystylis didn't come back this year. It must be shorter lived than the others. :-(

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