The Long-Blooming Garden: A Planning Tool for Pollinator Gardens

Part of the invisible beauty that runs through pollinator gardens is the spirit of reciprocity.  We gardeners, who have been given so much, shout out with our flowers, “Come!  Eat, drink, live! and be merry,”  calling in bees and butterflies, from near and far. And one of the most important considerations in our beautiful pollinator gardens is to try to provide food for as long as possible: pollen and nectar, from early spring to late fall.  Now to make sure we have a long bloom time, with a handful of species blooming all the time, we need a sense of which and how many flowers will bloom when.  Oof -my brain is starting to feel complicated. If you are like me, a task like this requires a little planning.

Thinking About Planting Seeds

There is no better time than November to start thinking, planning, and ordering seeds for next spring’s garden.  Why seeds?  Well, for me, I need to order seeds because I want a huge, crazy ton of plants (and I don’t think I’m alone in this!), and I don’t want to spend very much money. 

Trays of young plants
Easy to start a crazy ton of plants, hard to plant them all! I think about 90 trays were started this year in the picture for the local wildflower gardening club. All from little tiny seed packets.

While plants are typically $4 – $13 or more a piece (plus the crazy shipping costs!), a seed packet of 200-1000 seeds/future plants is $3 – $5 !!  And that is why I begin thinking about seeds in November.  But that’s so early!  The aromatic aster is still blooming!  Why November?!  The Cold Treatment is why.  

Aromatic aster still blooming while a bumblebee flies by.
Aromatic aster (Symphyotrichum oblongifolium), still blooming! What a champ!

Many seeds require something called a “cold treatment” in order to germinate.  A future post will discuss how to do a cold treatment, but just quickly here: for a cold treatment you get a little bag, label it, put some damp sand or vermiculite in the bag, mix your seeds with the sand, and then, depending on the species, you refrigerate it for typically 1 to 3 months.  Then you get it out and plant your seeds.  This mimics winter and breaks the dormancy of the seeds so they are ready to germinate. Without it, germination rates can be lousy, or even Zero! 

So, working the timetable backwards, if we want to start planting our home-grown plants out in about mid to late April, we should probably start our cold-treated seeds about March 1st, let’s say.  Many wonderful, awesome species require a 60 day cold treatment, so to make that March 1st deadline, they need to go into cold treatment about January 1!  Hmm!  So Here We Are, Late-November, trying to figure out bloom times and garden designs and seeds orders.  No problem.  We’re right on time.

The Beautiful Spreadsheet!

In a previous spring post about Planting a Pollinator Garden: The Quick Start Guide, I mentioned how useful a spreadsheet can be for  determining where gaps are in your garden’s blooming, but in the spring, I did not want to blind you with the full glory of the spreadsheet, because it is truly most useful now, for fall planning.

Here is an example of a garden spreadsheet for a “quick pollinator garden” which has a number of species in bloom throughout the season. It was created simply by cutting and pasting the desired species from the larger Flowering Times spreadsheet, which is linked further on, and then organizing them by bloom time.

Using a spreadsheet like this is an adaptation of a planning technique shown in Planting: A New Perspective by Piet Oudolf and Noel Kingsbury, a really useful book by two extraordinary gardeners. And looking at the spreadsheet above, we see that in this garden there will be about 6 or 7 species in bloom through summer, but that the spring looks like it could use some additions to increase species diversity.

I’ve found this type of flowering time spreadsheet really useful for visualizing the garden over time: which species will bloom when, how long the garden’s bloom time will be, and how biodiverse the flowers are at any moment, spring through fall. And understanding and planning your garden in time means that the insects who come to your garden can stay possibly their whole lives (what a nice thought), and you can enjoy abundant insects and flowers all gardening season long.  

Variety in species and flower types is important because there are a variety of pollinators with different sized bodies (and tongues!) and they can’t all access the same flowers. Here’s a mid-summer mix of great coneflower, blanket flower, common milkweed, wild quinine, purple coneflower, prairie blazingstar, star coreopsis, and anise hyssop.

The Big Flowering Times Spreadsheet!

A list of native perennials’ bloom times. Flowering times are based on my Mid-west experience and info from mid-western nurseries, so bloom times may need altering based on your regional climate!

Above is a section of the Flowering Times spreadsheet you can link to and/or download to help with planning.  It is a compilation of many species’ bloom times, plus a little extra planting information. The Flowering times shown are based on my Mid-west experience and info from mid-western nurseries, so bloom times will need altering to match your local bloom times. And many species are listed, but by no means, are all species included -feel free to add them!  And if you see any ways you’d like to make the main document better, please let me know, and I can make you an editor of the Flowering Times spreadsheet.  Many hands make light work, or maybe many hands just make work more fun.

Luckily, some early spring bloomers just plant themselves. These are spring beauties, Claytonia virginica.

So! To check out your planned garden’s bloom time situation, you can just find all the species you’ve got your heart set on, cut and paste them into a new spreadsheet, organize them by bloom time, and voila! A way to see what will be blooming when. Good for pollinators, but great for garden design: for co-ordinating flower combinations, plant arrangements, and so on. I know I’ve spent a lot of time over the last few years, staring back and forth, from my helpful spreadsheet to my garden map, trying to visualize what each month will look like. And on that note, I guess I better get back to it.

What is your favorite native? and why? Always looking for recommendations this time of year!


Planting: A New Perspective, by Piet Oudolf and Noel Kingsbury

Prairie Moon Nursery

Missouri Wildflowers Nursery

Prairie Nursery

23 replies on “The Long-Blooming Garden: A Planning Tool for Pollinator Gardens”

Nice! Thanks!

2 suggestions (but each suggestion does double-duty, so it’s sorta 4 suggestions):
1a. add an “Include” or “In Garden” column. The gardener can put an “X” or a “1” (or whatever) in this column to indicate a plant that he has or plans to have. Then, he can sort or filter on that column to see all of those plants together.
1b. Use the CountA function in a cell at the bottom of this column to count the number of plants included.
2a. Instead of coloring each cell w/ blooms, foliage, or winter interest, put a code letter in each cell (e.g. B, F, & W). Set up conditional formatting to automatically color those cells purple, green, or brown. Make the color of the font match the color of the fill so the code isn’t visible.
2b. Find a function that counts marked cells in each of the flowering time columns that also have a mark in the “Include” or “In Garden” column. I’m not sure I explained that well & it’s late. The idea is to end up w/ a count of the included plants that will be in bloom, have interesting foliage, etc. for each time period.


Thanks for these ideas, Brad! The way I’ve found it most useful is to just start a new sheet and copy and paste what I am planning to include in that particular garden, but the columns with Xes for sorting are also a good idea. It would help if people wanted to sort by early summer, mid summer, I agree!


The secretary in me loves you for this spreadsheet. So much potential, i.e., I am thinking of adding columns for what insects the plants are host for and you’ve done such a lot of work getting me started. Your gardens are stunning; a real inspiration.


Thank you so much! I am so glad you will be able to use this. A column with insect hosting information would be really great! If you do get to making that column, please let me know, and I’d be very happy to make you a spreadsheet editor as well, and that could be added in!


Thank you for a useful worksheet.
I wanted to download it so I could plan a pollinator garden, but I could not figure out how to download it to my desktop. It would only let me download to my unused Google account on-line. Am I missing something?
Thank you for any help figuring this out.


Hi Jill,
I think when you are at the document, if go to file, and then go to download, a number of different options should come up, like downloading it as an excel spreadsheet. Hopefully that will work! Thanks!


Hi Kelly, That is a really great idea!! I have seen the webpage and their spreadsheet (it’s a big one!). That would be so useful! Thank you for working on that! And what a good thing to be obsessed about! I’ll set it so you can edit it, too. You and Darlene have got me thinking of other columns to add, too, like the lepidoptera host plants, “especially good for bumblebees,” maybe links to pictures of plants would be useful? But I totally agree, the specialists bees would be awesome. Thanks for writing and working on the spreadsheet!


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