It’s Time for Perennials – The May Garden


I bet you are in the swing of gardening here in May.

You just finished all the garden chores, cleaning up debris, edging beds, adding amendments to the soil with compost, topping off with mulch, weeding, dead-heading, cutting back spent plants, dividing, thinning and transplanting, and now you want some NEW PLANTS.

But you have run out of room! What to do? A few choices come to mind. Cut back or prune tall perennials early before they bloom for a shorter display, or simply, find another plant that fits and remove WHAT DOESN’T!

One might now choose your favorites to keep and replace those not performing with new better improvements. Mid-May is a great time to do this in our area.

The rule of thumb on perennials worth the space they take up is they should have extended period of bloom or extraordinary flowers. Additionally they should have other attractive features throughout the season, from good form or structure, to great foliage, nice texture, wonderful fall color or colorful seasonal berries. And don’t forget about their benefit to wildlife! It is not all about a plant’s aesthetic value.

This is what hybridizing has predominately done for our plants. A hybrid plant is developed by crossing two species, which results in some characteristics of each parent plant and possibly creating something quite different. It made plants better in many cases. But not all cases.

This is where the choice comes in. Do we go with the old standby plants of our grandmother’s garden, or do we look for better behaving cultivars? Do we sacrifice fragrance or berry production if choosing cultivars?

By choosing cultivars, gardeners know exactly what they’re getting, without the variation and sometimes unsightly growth of certain native species. Cultivars let you design your garden for maximum impact and less worry of plants over-taking their bounds. Of course, that is not always the case with certain cultivars like some goldenrod, monarda, gooseneck loosestrife, carex or tradescantia. These cultivars can be garden thugs, just like the wild counterparts.

Most well-behaved cultivars are like garden ornament in a way, where you add the dazzle, but not the headache. Some cultivars are nativars (near natives) of a native like those just mentioned, but with a more favorable, pleasing and expected growth behavior. Certain monardas are an example.

Improvements have been brought to many old-time favorites like coralbells, columbine, coneflower, and daylily most notably. As you are out weeding, digging, and watering your perennial gardens, think about which plants are truly performing. Think where a new choice could be the answer.

If you are out dividing the old standby plants, do remember if plants are already growing tall or flowering soon, wait until they have flowered before digging in that cutting spade. Baptisia, Campanula, roses, and other early bloomers need you to pump the brakes for a bit. But do some pre-emptive pruning if you have aster, sedum, some salvia, monarda, goldenrod or phlox to make them less tall in bloom or yield them shapelier. Maybe more on this topic later…

The show opened and the stage is set on my garden this May. The entire ensemble is starting to arrive, a few still are on standby. Stay tuned, more images on the way up until Fling time. What will still be in bloom? Next post… how I deal with my heavy clay soil to have all that you see blooming.

About Garden Walk Garden Talk

I love to photograph, paint, draw, design, garden, travel the world, and pass on a few tips and ideas that I learned through experience as a Master Gardener and architect. I am highly trained in my field and enjoy my work each and every day. I garden in Niagara Falls, NY in zone 6-B. Find me at:
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28 Responses to It’s Time for Perennials – The May Garden

  1. I’m still out there cleaning up, but your pictures are inspiring me!

  2. Good tips. Iris is one of those plants that don’t bloom very long, but has such a spectacular flower that it’s worth having in your garden.

    • Individual blooms yes, but the number of cultivars is numerous, not to mention one healthy stalk of Bearded will produce 6-8 flowers easily. Dutch, Siberian, Bearded, Japanese, Reticulate-bulbed (subgenus Hermodactyloides) irises are very early, and many more. Not being a collector, I am sure I am forgetting some good ones. Some rebloom in fall too. I think the garden could easily have iris for a long season. My miniatures were blooming early May, now the bearded are starting. Siberian are coming.

  3. Kamila Pala says:

    It looks fantastic! 🙂 Nice set of photos and good inspiration, bye, Kamila

  4. Loretta says:

    Gorgeous, your posts are always so inspirational and full of knowledge. It is also known that some perennials should be cut back even before blooming as it will give it a sturdier and more successful bloom time? I’m thinking mums and black eyed susans and a few others spring to mind. What do you think? I also divided my enormous hosta today as it was taking up too much room in one area. I hope I have not done it a disservice.

    • Thank you, Loretta. Yes, mums and Rudbeckia get multiple haircuts a few times before bloom time. I use July 4th as an endpoint to stop shearing-back because it is easy to remember, but make sure that they are cut early in the season too. Cutting them back encourages branching which makes them sturdier too. I have not been cutting Rudbeckia back since we have had so many years of little rain. When drought years are on us, the plants bloom great but on much shorter stems. They withstand wind better and also help keep the dry soil from eroding since they are so numerous. Being numerous keeps the soil cooler and retain moisture by shading. I may have a post on this at some point. I get so many searches here on GWGT with questions like this. Oh, and nothing really hurts Hosta. The toughest plant around. I divide them all year, but would not tell others to do that though.

  5. M@Home says:

    Very nice! Autumn has started, actually it is almost winter, and all I now want to do is go prune our overgrown (dead-on-the-inside) plants that we’ve inherited with our new house! Looking forward to when the time is ready here.

    • Autumn is a favorite time of year for me, more so than either spring or summer. I get to enjoy the garden a bit more, so I have tons of plants blooming then. Spring and summer are too busy with work, so I spend less time after the initial cleanup. Travel takes me away most years in May, so I have missed iris, tulips, allium and peonies most years. This is my first May home in six years.

  6. All good points. I really didn’t use many herbaceous perennials or natives in my early designs or on my home properties. When I started blogging my design attitude changed exotics to natives/cottage perennials and especially north american mono-cots.

    • I have many native plants, but they are the cultivars rather than straight species. Only a few true natives in my tiny garden. I really do like your prairie plants though. They would look very out of place here.

  7. Well, you know I like the wild and rambunctious plants, but I do have some well-behaved cultivars mixed in as well. I just have to keep an eye on them so they don’t get smothered.

    • I found I had to remove the very aggressive native plant cultivars. I found it is almost impossible to keep up with them as they always return. Tradescantia is terrible. It is even in the back garden and I am unsure how it got there. Must have been a root cutting that missed disposal. Same with the supposed to be under 3 foot tall goldenrod that must have reverted and grew 5.5 feet tall and seeded everywhere. Three years is all the the time is spent dwarf sized and behaved. Then it was like an out of control teenager.

  8. Yes, my knees are sore from the weeding, trimming, planting of annuals, etc.
    Love all your flower combinations. The colors go so well together and very well planned out.
    And you forgot to mention poppies also being a garden thug. Your photo reminded me of them. I just can’t believe where they show up in other gardens areas of your garden. No wonder they are called poppies. They pop up all over! And it seems like once you have them you can’t get rid of them. I have several perennials on the list that you mentioned that are garden thugs. Right now I’ve been trying to get rid of the Chameleon plant.

    • I never had poppies get too frisky. The heavy clay soil keeps that tap root from going deep. I have them out front too and they never moved from their spot. Yes, far too many nativars are thugs. I think in time they may revert. Too similar to the species after a time. I have to check if this is possible where they cross bred and take the traits of the species once again.

  9. A.M.B. says:

    Great post! The garden is new in my yard, so I haven’t run out of room yet. It’s time for some thinning in my mother’s garden, though (and I hope to transplant some of what she doesn’t want into my garden).

  10. Indie says:

    You have such a lovely garden! With my new garden, I am still in the filling up stage. I have yet to run into the problem of running out of room, but I still do like interesting cultivars that give a little more added beauty or benefit. I have benefitted from other gardeners who have mature gardens and are looking to thin out their plants, though! I love getting plants from other gardeners!

    • Thank-you, Indie. That is what is so wonderful having a new clean slate – putting in just what you want. My job affords me getting most things cost free, but that is also what led to having a garden so full. If you have the same with your friends’ gardens, it won’t be long until you end up with no room to spare.

  11. Karen says:

    Your gardens are always so beautiful…sometimes being heavy handed leads to good things. 🙂

    • I do like full and lush. It is a place I experiment on what works for gardens I design. In my design work, I work on all elegant estates and it is completely different and more restrained. Many bloggers would not find those gardens as interesting I am sure. Too much open space, long views and turf grass. Sure there are drifted beds, meadows and wonderful woodland garden spaces, but in between is grass expanses.

  12. rose says:

    Your garden is gorgeous, Donna! I’m a plantaholic, and every spring I am tempted by all the new plants to buy even more. But I’ve run out of room, too, and don’t have the heart to pull out some plants that aren’t doing their job. I have been pulling out purple coneflowers, though, one of my favorite plants, but they’re re-seeding everywhere! I think the only solution is to create another flowerbed:)

    • Thank you, Rose. I am not a plantaholic, but I like to experiment with plants for design so that gets me into collecting far too many of them. It is good because I do find out rather quickly what plants do not perform well or last over time. I find out which plants become thugs (so as not to use these on the wrong sized properties) and also to work up nice vignettes. I find out that some plants that have problems in other areas don’t have the same problems here. You get lots of purple coneflowers, but here they peter out over time for instance. I do try new cultivars of them to see if any will persist in gardens here. ‘Magnus’ never lasted in my garden for very long. Now we have have problems with aster yellow disease. Not worth having them if they all come out distorted looking.

  13. Looking beautiful Donna…I wish i had my chores done…far behind with the very crazy weather…oh well my weeding chores await with loads of mosquitoes this year…seems they are as prolific as the weeds this year.

  14. Hello Donna,

    You always come up with good and something new ideas. It’s a good thing that we have to maintain our garden with seasonal flowers, but first we must keep our garden clean. I appreciate your blog and forward looking for more.

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