Roundleaf Four O’Clock: A Rare Colorado Native Worth Protecting
Meet the roundleaf four o’clock (Mirabilis rotundifolia), one of Colorado’s most elusive native wildflowers. This little-known perennial might not be splashed across every gardening magazine, but for native plant enthusiasts and conservation-minded gardeners, it represents something truly special – a living piece of Colorado’s unique botanical heritage that’s hanging on by a thread.
What Makes This Plant So Special?
The roundleaf four o’clock belongs to the fascinating four o’clock family, known for their evening-blooming habits. True to its name, this herbaceous perennial features distinctive rounded leaves and produces small tubular flowers that open in the late afternoon and evening hours. Like other members of its family, it puts on its best show when most gardeners are winding down for the day.
This Colorado endemic is a true forb – a non-woody perennial that dies back to ground level each winter, only to emerge again from underground parts when conditions are right. Its low-growing habit and compact form make it well-suited to the rocky, challenging environments where it naturally occurs.
Where Does It Call Home?
Here’s where things get both exciting and concerning: the roundleaf four o’clock is found only in Colorado, making it a true state endemic. However, its distribution is extremely limited, with botanists documenting only a handful of populations scattered across the state’s mountainous regions.
A Plant in Peril
Before you start planning where to plant this unique native, there’s something crucial you need to know. The roundleaf four o’clock carries a Global Conservation Status of S2, which translates to Imperiled. This means the species is extremely rare, with typically only 6 to 20 known occurrences and very few remaining individuals – possibly as few as 1,000 to 3,000 plants in the wild.
This rarity status makes the roundleaf four o’clock a plant that requires our utmost respect and careful consideration. Its precarious position in the wild means that every individual plant matters for the species’ survival.
Should You Grow It?
The short answer is: only if you can source it responsibly and ethically. Given its imperiled status, removing plants from wild populations would be devastating to the species. However, if you can obtain seeds or plants from legitimate conservation programs, botanical gardens, or specialized native plant nurseries that propagate from ethically sourced material, growing this species can actually contribute to conservation efforts.
Here’s why you might want to consider it (with proper sourcing):
- You’ll be growing a piece of Colorado’s irreplaceable natural heritage
- Evening-blooming flowers provide nectar for nocturnal pollinators like moths
- Perfect conversation starter for fellow native plant enthusiasts
- Contributes to ex-situ conservation efforts
- Unique addition to specialized rock or alpine gardens
Growing Conditions and Care
If you’re fortunate enough to obtain ethically sourced roundleaf four o’clock, you’ll need to recreate its native mountain habitat as closely as possible. This plant has evolved in Colorado’s challenging high-elevation environments, so it has specific needs:
- Drainage is everything: Provide extremely well-draining, rocky soil that never stays soggy
- Full sun to partial shade: Mimics its natural habitat conditions
- Hardy in USDA zones 4-7: Can handle cold winters but may need protection in cultivation
- Low water once established: Drought-tolerant like most high-elevation natives
- Rocky soil preferred: Add gravel, sand, or decomposed granite to improve drainage
Garden Design Ideas
The roundleaf four o’clock isn’t your typical border plant – think of it more as a botanical gem for specialized settings:
- Rock gardens: Perfect tucked between stones where drainage is excellent
- Alpine plant collections: Ideal companion for other high-elevation natives
- Conservation gardens: Showcase rare and endangered plants
- Native plant demonstrations: Educational tool for Colorado’s unique flora
The Bottom Line
The roundleaf four o’clock represents both an opportunity and a responsibility. While it’s not a plant for every garden or every gardener, those with a passion for conservation and native plants can play a role in its preservation – but only when approached with the respect and care this rare species deserves.
Remember: never collect from wild populations, always verify your sources, and consider this plant as part of a broader commitment to protecting Colorado’s native plant heritage. Sometimes the most rewarding plants to grow are the ones that challenge us to become better stewards of our natural world.
If you can’t source this rare beauty responsibly, consider other Colorado natives like blanket flower, Rocky Mountain penstemon, or wild bergamot – they’ll give you that native plant satisfaction while being much more readily available and conservation-friendly.
