Gillette's Habitat GardenOhio / Phenology / 01
Find the weeks
your garden goes quiet.
Check off the plants already growing in your garden. The tool maps their bloom windows and shows you what could carry the season through. Both natives and non-natives are included, because some non-native perennials are genuinely good for pollinators. Filter by native status if you'd rather see only one or the other.
What the results mean
Bloom timing is based on Columbus, zone 6b. Treat it as a general guide for the rest of Ohio. The list includes native and non-native plants, so check native status before you buy.
01What you grow
115 plants availableCheck off what already grows in your yard. The tool shows which of the season's 16 bloom windows you cover and which plants could fill the rest.
Select what is already established
Tells the tool what to recommend. It doesn't limit which plants you can check.
How this tool works
I'm Tyler Gillette, a wetland ecologist and environmental consultant. I've been converting my own yard in Columbus, Franklin County, Ohio into habitat since 2023.
This tool is a work in progress. The dataset is 140 plants and it will grow. If a plant you grow is missing, if a bloom window doesn't match what you see in your own yard, or if there's something the tool should do that it doesn't, tell me: tyler@gilletteshabitatgarden.com. Field observations from other Ohio gardeners make this better than any published range can.
The Bloom Gap Finder maps when the plants in your garden are actually in bloom, then shows you the stretches when nothing is. Those quiet weeks are when pollinators go hungry.
Here's what's behind the numbers.
Herbaceous plants only. No shrubs, no trees. A few short-lived plants are in here. Jewelweed is an annual and tall bellflower is a biennial, and both reseed reliably enough in Ohio to hold a bloom window. Leaving jewelweed out would mean pretending the best late-season hummingbird plant in wet shade doesn't exist. Woody plants are a different decision at a different scale and cost, and mixing them into a perennial bed calculation would muddy both. Willow and red maple feed bumble bee queens before most perennials break dormancy, so if your March looks empty here, a native willow is the honest answer.
Bloom isn't the same as food. A plant in bloom isn't always a plant that feeds much. This tool tracks timing, not forage value.
Mid-March through mid-November. Outside that window there's essentially nothing herbaceous blooming in Ohio, and pretending otherwise would build in a gap you can't fill.
The end of the season is thinner than the start. After mid-October the options narrow fast, and past the first week of November this dataset has one plant that reliably carries bloom: frost aster, which wants full sun. If your late-fall window is empty and your yard is shaded, that isn't a gap a perennial will close. Leaving seedheads and stems standing does more for overwintering insects at that point than anything you can plant.
Bloom windows are calibrated to central Ohio. Franklin County, Zone 6b. If you garden farther south, things run a few days earlier; farther north, later. Urban gardens run ahead of rural ones. Treat the dates as a reliable shape, not a calendar.
Where the dates come from. Bloom windows are interpolated from published flowering descriptions in Illinois Wildflowers and the Missouri Botanical Garden Plant Finder, then adjusted for central Ohio latitude and standardized into half-month blocks. They are derived estimates, not dated field records. No systematic Ohio phenology dataset exists for most of these species, and closing that gap would mean working from USA-NPN observations or dated herbarium sheets. That work hasn't been done yet. If one is wrong in your yard, tell me.
Only reliable bloom counts. Plenty of species throw a few flowers well outside their main season. That's real, but it isn't forage a pollinator can depend on, so sporadic rebloom doesn't count toward coverage.
Two dates per plant. Every plant here has a possible bloom window and a reliable one. Only the reliable weeks count toward your coverage, because a pollinator can't plan around a good year. If a plant is flowering in your yard during a week this tool calls quiet, that's why. It might cover it. I wouldn't count on it.
Coverage measures continuity, not quality. A filled block means something is blooming. It doesn't mean it's blooming well, or that it feeds the specialist bees that need a particular plant. A garden with perfect coverage and no milkweed still has a problem.
Non-natives are included. Some non-native perennials are genuinely good for pollinators, and pretending otherwise doesn't help anyone plant a better garden. You can filter them out if you want, and the Non-native labels identify introduced plants.
Wetland codes and garden moisture are two different things. Each plant shows its National Wetland Plant List code, which describes where the species occurs in the wild in wetland delineation terms. It does not describe what it needs in your bed, and the two disagree more often than you'd expect.
Orange coneflower carries an obligate-wetland rating in the Midwest and still grows fine in ordinary garden soil. Scarlet beebalm carries an upland rating and still wants steady moisture. That isn't an error in either number. Wetland ratings are regional, they're built for delineation rather than horticulture, and a plant's tolerance is wider than the range it usually occupies in the wild. Where the two disagree, plant to the moisture rating.
Common questions
What is a bloom gap?
A bloom gap is a stretch of the season when few or none of the plants in your garden are flowering. You can have a garden full of flowers and still have weeks with little available for pollinators.
That matters because bees, butterflies, moths and other insects become active at different times and need food across the whole growing season, not just during the summer flush. Pollinators need steady bloom nearby, or they forage elsewhere. Early spring and late-season gaps are often the most important to fill.
The goal is not something blooming every single day. It is spotting the quiet stretches and deciding whether to fill them.
When do Ohio gardens usually go quiet?
Most Ohio gardens have their biggest gaps in very early spring and late fall, with quieter stretches between major bloom waves. Exact timing varies with weather, location, soil and the plants you grow. Ohio State's phenology calendar shows how much bloom timing shifts with accumulated heat and location.
In my own yard, very early spring and late fall are my main gaps too. Sunny beds are easy to fill. Shade is harder, and getting successional bloom across the whole season there is still a work in progress.
How do I use the Bloom Gap Finder?
Check off the plants you already grow, and the tool shows when they bloom and where your garden goes quiet.
- Check the plants you already grow.
- See when those plants typically bloom.
- Find the stretches with little or no bloom.
- Use the suggested plants to explore options for those windows.
You don't need to rebuild your garden. The tool answers a simple question: if I want more flowers in this window, what could I grow? It is a starting point that saves hours of searching and compiling on your own, and it can point you toward species that aren't on the list. Your actual garden is always the final test.
Why does it include non-native plants?
The Bloom Gap Finder maps when a garden flowers, and many Ohio gardens already include non-native plants, so leaving them out would give an incomplete picture.
Native plants are the foundation I recommend for habitat, and conservation guidance supports prioritizing regional natives and diverse bloom times. But some non-native plants are used by native insects, and they can bridge gaps when natives aren't blooming.
That is why the caution line is there. A plant appearing in the tool does not mean it offers the same habitat value as a regionally appropriate native. Bloom timing is only one part of habitat value.
Will the bloom dates match my garden?
Not exactly. The bloom dates are adjusted for Columbus, Ohio (zone 6b), where I garden.
Bloom timing depends on temperature, growing degree days, microclimate, soil, moisture and exposure. If you're in Cleveland, Cincinnati, Athens or Toledo, treat a date as approximate, not a promise. Farther north, blooms tend to come later. Farther south, earlier. The farther you are from Columbus, the more the bloom sequence matters over the exact dates.
Your own garden is the best calibration you have.
Who built this, and where does the data come from?
I built the Bloom Gap Finder. I'm an Ohio wetland ecologist and environmental consultant with nine years of field experience, and I built it after noticing that a garden full of flowers doesn't mean flowers all season. My yard looked better, and drew more pollinators, at some times than others.
The tool combines bloom period information from published reference sources adjusted for central Ohio in a structured plant dataset. It is a planning tool built around bloom timing. It doesn't predict exactly when every plant will bloom, and it doesn't measure overall habitat quality. The full references are on the References page.
Use it as a starting point for your research before you spend money on your garden.