Cultivating Hydrangeas

Hydrangeas of varying types have to be the most widely grown summer flowering shrubs of all. How so? The numbers of cultivars bred from the species serrata, macrophylla, paniculata, arborescens, anomala (climbing hydrangea) and quercifolia (oakleaf hydrangea) surely number in the hundreds. The numbers of those hybrids and cultivars commonly available for sale are staggering. And it seems that every year new cultivars are offered for sale. Should you be interested in hydrangeas for your garden, there are many from which to choose. I am by no means complaining. A warm sunny late July day in my zone featuring a blue sky and the hydrangeas in bloom is one definition of a Michigan summer garden. The spring in Michigan is breathtaking for the sheer number and diversity of plants that break dormancy, come on, and bloom. And of course the June garden features the peonies, roses and delphiniums, and countless other perennials. The July and August garden is ruled by the hydrangeas, much to my delight. I do love these robust growing shrubs that grow and bloom profusely. My hydrangeas make me look like an accomplished gardener, and ask for little in return.       That said, I am fairly selective in what varieties I plant. The short version is that I avoid any hydrangea that blooms on the previous year’s growth. Michigan winters can and will kill the latent flower buds. Pink and blue hydrangeas may do well for you, but they are underwhelming for me. I tend to stick with just a few of the available white blooming cultivars. Hydrangea paniculata, notably Limelight, and its compact relative Bobo, is hardy as can be. These cultivars are overwhelmingly generous with their flowers. They are solidly hardy in my zone. My Limelight hydrangeas in my front yard have been there over 20 years, and endured every one of my pruning experiments. I try to dust them with Hollytone in the spring – but if I forget, they grow and bloom anyway. If I am late with the water, the wilted leaves let you know to get out the hose and use it. Should I cut the blooms, they are gorgeous in a vase. The aftermath of a vase full of hydrangeas is a vase full of dry hydrangeas.

I have a number of clients with Limelight hydrangeas on standard in containers. A number of them choose to overwinter them in their pots, against my advice. I am not a fan of overwintering any plants in pots in my zone. Very few plants can tolerate their roots being above ground during our winter. My worries were unfounded. All of those hydrangeas spending the winter in pots came on without skipping a beat. Our past winter dealt a lot of damage to woody plants. I lost the entire top of a picea mucrunata – shocking, this. Four boxwood burned and died near my front walk. It was a sleeper tough winter. I was shocked at the extent of the winter damage this spring. But the hydrangeas in pots did not skip a beat. One pair has been in pots for 8 years now. Really? That is what I call the willingness to be. I decided to try them myself, both at the shop, and at home. Our grower prunes them after they flower, in July, and again early the following spring.  This routine keeps the heads compact and dense.

Cultivating hydrangeas is not that difficult. Site them with more sun than not-meaning 6 hours a day of good sun. . They do like that sun to bloom well. Hydrangeas can be quite shade tolerant, but those in a lot of shade have weak stems and sparse flowering. Have a lot of shade? Try the oak leaf hydrangea. All of the cultivars of Hydrangea quercifolia are very tolerant of low light. The oak leafs are reputed to do very well in southern US locations. They are easy going about the soil composition, but soil that is enriched with organic matter is optimal.  Being large shrubs with a full complement of large leaves, they need a regular supply of water. Don’t be fooled by their wilting leaves on a very hot day. Those big leaves are thin, and they wilt from heat. If they perk up once the sun goes down, and the weather cools, leave the watering for another time. Hydrangeas of one kind or another in my zone have been blooming or are about to bloom for several weeks. Annabelle hydrangeas typically bloom in June here. A very cold spring set the bloom date back a bit, but all of the rain attending that chill resulted in luxuriant growth. The cultivars known as Bobo (a dwarf relative of Limelight) and Incrediball (a more upright and strong stemmed version of Annabelle). The Little Lime hydrangeas are budding up, and will be in bloom soon. As much as my clients might want pink or blue hydrangeas, I discourage planting hydrangeas in my zone that bloom on old wood. Our winters can be breathtakingly cold and hard. The shrubs will survive. The flowers not so much. The Bobo hydrangeas pictured above bloom profusely. The white florets have a decidedly greenish cast. The color of the creeping jenny on these stone stairs echoes that green.

These Bobos are planted in full sun. Do not try this at home unless you have the patience and dedication to monitor the water closely. The flowers will burn and go brown if the plant lacks for water. Some afternoon shade is a good idea. If you have the room, massing hydrangeas can be an especially dramatic look. Their are no hard and fast rules about the spacing. The mature size of a Bobo is 3′-5′, so spacing them at 4′ apart will result in a billowy and undulating hedge. Spacing them at 36″-42″ inches on center refers to the distance from the center of one plant to the center of the next. This spacing will produce a denser hedge or mass. There are pros and cons to every spacing decision. But it is worthwhile to note that hydrangeas grow very fast.

A hydrangea of decent size in a nursery pot means the plants are most likely root bound. This means they will need to be watered faithfully, maybe daily, until they settle in. That water needs to be applied directly to the root ball. A newly planted hydrangea that goes dry can react with singed leaves and flowers.

Enough sun and water and some moisture retentive soil is all they ask for.

A mass of Bobo hydrangea

Even the north sides of these south facing hydrangeas bloom well.

mass of hydrangea Incrediball

On my driveway, a Limelight hydrangea on standard is getting ready to bloom.

Comments

  1. Deborah,
    My gardens now include Limelight, Bobo, and Little Quickfire due in no small part to the commentary you’ve provided in your posts which I carefully studied prior to planning my spaces.
    My hydrangeas bring me a lot of joy; thank you for the role you have played in that process.
    Gratefully,
    Suzanne

  2. Sonya Peel says

    Deborah, what is the ornamental grass that you have growing around the stone walled Bobo Hydrangeas? I like how that combination looks and may use it on a lengthy berm that I am getting ready to plant with shrubs, small trees, ground covers and ornamental grasses instead of Bermuda Grass. Instead of Bobo, I plan to use Little Lime panicle hydrangea as I think it may handle the sun a little better better. I love following your blog.

    • Deborah Silver says

      Dear Sonia, I answered the question about the grass in a comment below. Bobo is a panicle hydrangea. I am not so much a fan of Little Lime, as I think the color is much more cream than white. best, Deborah

      • Sonya Peel says

        Thanks, Deborah. Sorry, I missed your response to Greg. I planted a small grouping of Pennisetum alopecuroides ‘Hameln’ in one of my beds and loved it last year. This year, not so much as they are struggling – lost a couple. I was looking for a replacement. I live in North Georgia (7a/8b), so they should be hardy here.

        • Deborah Silver says

          Dear Sonya, we always loose a few in this garden every year. I cannot speak to conditions in north Georgia-talk to a good nursery person in your area. best, Deborah

  3. In your final photo, was the hydrangea on standard overwintered outside in that location?

    • Deborah Silver says

      Dear Heather, no. This is the first time I have planted a hydrangea standard in this pot. best, Deborah

  4. Gail Lemon says

    Hi, I found this article to be very interesting. My sister got me a strawberry vanilla Hydrangea and it is still potted, and growing new leaves nicely. I live in zone 5. The question I have is why do the leaves keep turning yellow. I pick them off and burn them. I read it was a lack of iron so I got some feed it and it was doing better. We had a hard rain and today I noticed 4 yellow leaves again. What can I do to stop this?. I would like to keep it potted When we live is all sand. Thank You

    • Deborah Silver says

      Dear Gail, inner leaves that turn yellow can signify too little water. Or too much water.If the hydrangea is root bound in its pots, it may need a larger pot.As for the heavy rain and yellow leaves-be advised that plants rarely react instantly to water conditions. The hydrangea may have been to dry before the rain. Shedding interior leaves is an effort the plant makes to reduce the numbers of leaves that need water. I do not think you need to burn those yellow leaves. best, Deborah

  5. Donald Souza says

    Deborah, I have traditional hydrangeas in my yard for many years but this year I tried potting a variety called Strawberries and Cream. I don’t know the species name. They are in full morning sun and afternoon shade after 2PM. The flowers bloom but they die soon. I water them daily. I decided to cut the dead flowers and the leaves underneath are green and new leaves are sprouting. Can you please help or give me any info on them. I would appreciate any help or advice. I live in Massachusetts. Thanks.

    • Deborah Silver says

      Dear Donald, I am too far away to help you, nor do I have any experience growing in your zone. But I do know this is a very large growing plant-up to 7′ tall and 5′ wide. I don’t know what size container you have it in,but if the container is small, it will never be happy. I would read up about them on line. best, Deborah

    • Donald Souza says

      Thanks, I appreciate your help.

    • Dear Deborah – three years ago we planted a number of Endless Summer Blushing Bride hydrangeas at both the front (west facing) and back (east facing) of our house. They have not bloomed in the three years. They have nice lush green foliage but this year we have 2 blooms on 18 plants. They seem to set buds but the buds dry up. The only new growth comes from the bottom of the plant. I mulch the base of the plant with dry leaves in the fall. We live in Southern Ontario near Waterloo. Are they not hardy enough to take our winters? We also have Annabelle and Invincible Spirit hydrangeas and they do beautifully. Thank you.

      • Deborah Silver says

        Dear Steve, your hydrangea is a cultivar of hydrangea macrophylla.They bloom on old wood, so do not prune after August 1. That hydrangea may be root and leaf hardy in my zone, but it is not flower bud hardy. I do not plant them, as they are not reliable to bloom. I do not know what you could do to improve the situation-except to replace them with hydrangea paniculata hybrids. That said, I do have a client who puts giant chicken wire cages around hers, and fills the cages to the top with leaves. She gets a good bloom every other year or so. She grows the old cultivar Nikko Blue. best, Deborah

  6. Keeping hydrangeas happy in 90+ degree heat is a challenge. I recently, poured a bag of mulch around the base of each bush and water a few times a week. The mulch is helping retain moisture and prevent wilt. Nothing worse than a wilting/sad hydrangea! If this heat is going to be our future reality, I might consider installing a drip system. How are others managing the heat’s impact?

    • I keep mine mulched . Mine are in full sun all afternoon . When I bought the house they were already there. They have grown since I moved in. Mulch & water is the key for the sun. Also fertilize early in the year. Again before the heat. Is my key.

  7. Charisse says

    Planting hydrangeas that flower on new wood is difficult even here in the south (Virginia for me). For the last several years we have had late frosts that killed the flower buds. In an earlier post you mentioned the limelight hydrangea and that is what I am am planting now and I rather like them, so thank you. I do have huge oak leaf hydrangeas that flourish for me in the woodland borders,, and the deer do not seem to bother them like they do all the others. I have been unsuccessful getting a climbing hydrangea on the brick chimney to flower in the 15 years it has been there. It is huge and I have tried everything to no avail. I think I am going to try growing a standard in a protected area. Thanks for the post.

    • I also have a climbing hydrangea that we have planted 4 years ago and has yet to flower and a very slow grower. It also does not like the Illinois winters, like me. I was thinking of taking it out and plant a clematis in its place.

  8. Sallie Boge says

    Dear Deborah,

    I love your Detroit Garden Works store. I love reading your blog too. Thank you for all the great information you share. I am a fan of Hydrangea paniculata (any and every variety). I have a question that takes this conversation off on a tangent: Do you or your readers have any recommendations, personal experience, or literature that I can read regarding whether or not Hydrangea paniculata can survive and thrive close to a Black Walnut tree? I am reading numerous sources, some of which contradict each other and others which say their information is based only on personal experience and not well-controlled, published studies. Anything you can tell me will be helpful.

    Kind regards,
    Sallie Boge

  9. Thank you for this info. What is the ornamental grass in the picture with stone wall and limelights? Beautiful simple texture and color with the limelights.

  10. Hi Deborah. Thanks for the hydrangea post. I just planted the Firelight hydrangea. I heard that it’s the 2019 hydrangea of the year and that it loves full sun. I can’t wait to see how it does. Do you have any suggestions on this type? I’m in Ohio. Right now it’s a nice shrub with healthy green foliage, there are just a few flower buds on it. Not sure if this is done flowering or if it’s just starting. Any help, tips or suggestions coming from you Deborah would be awesome. I’m a big fan of yours. Thanks for your inspiration. Your posts and flowers always make me smile.

    • Deborah Silver says

      Dear Brenda, I have not heard a thing about this variety, but I am sure I will if it proves to be garden worthy. I will look it up, thanks, Deborah

  11. Fran Baker says

    Hydrangeas have always been a favorite of mine. I’ve been growing Limelight’s here near Denver. I’ve a question about trimming Limelights….I usually trim them way back in the fall to like 6-8 inches, but they have to play catch up in growth again each spring, rather than gaining in height each year. What is your recommendation for trimming them in fall….should I only be taking off the blooms (I like to dry them)??

    • Deborah Silver says

      Dear Fran, I only prune limelights in the spring, and never prune them shorter than 24-30″ If you want a full sized shrub, then just prune lightly in the spring. Maybe 8-12″ off the top, and eliminate any crossing or damaged branches. Or, just remove the flower heads, as you say. It is not necessary to prune them that hard. all the best, Deborah

    • Theresa Gue says

      Deborah, I am so jealous of your breathtaking limelight hydrangea standards. I have my own, which has lived in a pot outside year-round for ten years (on a fifth floor roof deck, no less!), but came down with a terrible case of spider mites this year. It has lost 90% of its leaves and blooms, but I see it sending out new growth. They are tough little plants!

  12. Jane Andersen says

    Hi Deb,
    I totally enjoy hydrangeas as well. What frustrates me is the sizing of the plants. I need a plant that max’s Out at 3-4 feet but the websites differ on sizes of the same plant. Any ideas for a reliable webpage on sizes. I may end up trying Bobo

    • Deborah Silver says

      Dear Jane, there has been a lot of plant breeding in recent years for smaller sized shrubs. Bobo is an outstanding example of that, but the range is from 3-5 feet. I have seen them grow both sizes-but how big any plant depends on siting, soil, water and light conditions. all the best, Deborah

  13. Chris Boggs says

    Hi Debra,
    Love my hydrangeas too! Have been growing them for about 30 years. The paniculatas never disappoint!
    I too noticed the standards wintering over in pots, specifically at a commercial site in my area (near Toledo).
    I was bold enough to make a comment to the owner that it might be risky. Well, I am eating my words! Those ‘limelight’(and not even large pots) are beginning to bloom their hearts out!!

    Now, if only the deer would respect my love of hydrangeas

    Thank you for your observations, words and pictures. What a great read to start out this Monday morning.

    A fellow plant lover,
    Mrs. Chris Boggs
    Sylvania, OH

  14. Denise Wickline says

    May I ask what is underplated beneath your driveway Limelight on standard? Beautiful!

    Warm regards,
    Denise

    • Deborah Silver says

      Dear Denise, my hydrangea standards are under planted with white polka dot plant. best regards, Deborah

  15. Jeannine says

    Your pictures are beautiful! This year in my area, southern Ontario, the hydrangea are blooming bountifully. The Annebelle especially. They are just beautiful in everyone’s gardens. I have planted the pink and blue ones. Most years not many blooms but this year is different story. To my surprise more than I have ever had! I do love these beauties too.

  16. Kathleen says

    Thank you, Deborah, for the photos and information. I like the look of Pinky Winky hydrangea and their later bloom time. Can you tell me what the light requirements are for that variety and your experience with them?
    Kathleen

    • Deborah Silver says

      Dear Kathleen, I have never planted or grown this variety, so my opinion would be suspect! Maybe there is information about their ciltivation on line. best, Deborah

      • Kathleen-
        Have a Pinky Winky shrub for 10 years and it’s my fav. It situated at northeastern corner of house but blooms very well. Soil: Prefers good, loamy soil. Most adaptable of all hydrangeas to different soil types. Most urban tolerant and very difficult to kill. I’ve moved it twice and it’s not fazed.
        Pruning: Best pruned in early spring. Blooms on new wood. I don’t prune mine. Lovely vase shape topping 6 feet.
        Watering: Medium moisture. Not as water dependent as Hyd. Macrophylla. Will tolerant drought.
        Breeder: Dr. Johan Van Huylenbroeek at the Flemish DVP breeding station of Belgium

  17. Michaele Anderson says

    I can’t say enough good things about the various paniculata varieties and, even in the hot and muggy southeast, they don’t miss a beat. I grow 6 different named selections and ‘Limelight’ and ‘Bobo’ top my list. They are both super stars in flower production and the dried flower heads provide great winter interest. I always love seeing photos of how you use them in the landscape.

  18. Beautiful…I too love my hydrangeas. What is the grass planted below the Bobo in some of your photos? Thanks Deborah.

    • Deborah Silver says

      Dear Greg, it is a dwarf fountain grass. Pennisetum alopecuroides ‘Hameln’. Best, Deborah

Leave a Comment

*