Cooperia drummondii (rain lily)

The taxonomy on this friend is very confusing. I have seen multiple combinations of the genera names Cooperia and Zephyranthes, with the species name (second part of the two-part name) listed as pedunculata (which is listed as a separate Texas-only taxa in BONAP), drummondii, or chlorosolen. The cooperia name seems to be (I think?) the current official name so I’m going with it for now. I think drummondii or chlorosolen are the safest names to look for as the Oklahoma-recorded taxa as well.

Cooperia drummondii

How to grow

From seeds

I haven’t been able to get any to germinate in pots (one attempt in 2022) or by sprinkling on the ground (either that or they don’t like our habitat in the yard).

However, allegedly they can be quite easy and may not require any stratification or scarification. That extension service page also says they don’t keep well, so if you get them plant them soon.

From plants

I’ve only ever tried moving this out of a pot into the ground. Let me know if you’ve tried moving one of yours and whether it worked. Eventually I will get bold enough to divide my one and own plant.

Where they live

Moisture

  • Dry: yes
  • Medium dry: yes
  • Average: yes
  • Medium wet: yes
  • Wet: yes
  • Aquatic: no
  • Spring flooding: no
  • Winter drought: yes
  • Summer drought: yes
  • Drought reaction: no flowers

Light

  • Full shade: no
  • Part shade: yes
  • Full sun: yes

Soil types

  • Sand: yes
  • Loam: yes
  • Clay: yes
  • Shallow: unknown
  • Containers: yes
  • Potting soil: yes
  • Well drained: yes
  • Poorly drained: no
  • Nutrient rich: unknown
  • Nutrient poor: yes

Disturbance

  • The leaves are slightly succulent so I suspect too much stepping on would damage them.
  • Mowing - this can keep the habitat open so they are more visible, so they would be good as a “surprise” ephemeral in otherwise mowed lawns. I see them in mowed paths occasionally at my parents’, too.

Thatch and leafy layers

  • Probably less thatch to emerge through is easier, although ours comes up through a loose layer of sweetgum leaves each year

Temperature

  • This species has no above-ground parts in the winter. I’ve not tried growing them in pots.

Interactions with other plants

Can coexist easily with
  • Indigofera miniata
  • Silver bluestem
  • Annual ragweed
  • Oenothera macrocarpa
  • Buffalograss
  • Invasives
    • bermudagrass
    • crabgrass

Even in ideal habitat, can be outcompeted by

  • Helianthus maximiliani
  • Datura wrightii
  • Sorghastrum nutans
  • Solidago sp Saxon
  • Salvia greggii
  • I suspect Vernonia baldwinii would shade it out?
  • Invasives
    • Johnsongrass
    • King Ranch Bluestem? (Unclear, but I think it grows too densely, I’ve not seen any among it)

In its ideal habitat, this species can outcompete

Since it’s an ephemeral bulb, I think it’d be really hard to get a dense enough planting to have the leaves (the only part that stays up more of the year) to outcompete anything. Maybe some Sedum nutallii? But they don’t really like the same habitat.

Can this plant tolerate allelopathy by

  • Black walnut: unknown
  • Pines: unknown
  • Eastern red cedars: unknown
  • Invasives
    • Tree of heaven: unknown
    • Bradford pears: unknown
    • Garlic mustard: unknown

Where can I get for Oklahoma?

  • Ask a neighbor if they have any!
  • Unclear if seedlings can be moved from ground, let me know.

Plants (potted or bare roots)

Oklahoma
  • Unknown
Within one state
More than a state away
  • Unknown if available

Seeds

Oklahoma
  • Unknown if available
Within one state
More than a state away
  • Unknown if available

Find more photos and information

Other species, cultivars, and confusions

The NCSU website mentions a variety called “Fedora” that claims to be just a variety the Plant Delight Nursery found in Mexico, but the same species. It no longer appears to be for sale. I found a few other standalone and eBay websites selling seeds and bulbs, but I was really unclear whether the nurseries were reputable, since I’m less familiar with the decorative bulb world. (Yay for native plants getting into the decorative gardener world I guess though?)

An archived posting by TAMU Extension describes how to germinate all kinds of rain lilies (ours is named as the “Giant Prairie Lily”) and I think is a helpful list of other non-native rain lily names you might encounter @GrowingRainLiliesa.

Missouri Botanical Garden’s plant finder tool lists a [Zephranthes simpsonii] which appears to be a different species native to the extreme southeastern United States. They advise that it is quite rare in the wild and should only be purchased, never collected.

BONAP lists only Cooperia chlorosen (and has no drummondii) for Oklahoma. They have Cooperia pedunculata as a separate species for Texas only. One flora-type site says pedunculata and drummondii are synonyms, as does the NCSU extension site. Others specify pedunculata as a larger species and drummondii as a smaller one in the same area., , as does Lady Bird Johnson.

In general I think something named chlorosolen or drummondii is probably the one you want, with pedunculata being a maybe.

What is the function of Cooperia in the ecosystem…

in Oklahoma?

  • I see a lot of tiny bees on them when they bloom. I imagine it’s even better if you can get a whole array of them going; I only have a single plant with at most a few flowers at once.

in general?

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