Quand transplanter les hortensias, selon les experts en jardinage

Hydrangea with purple-blue blooms


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Catherine McQueen


Peu de choses sont plus emblématiques qu’un jardin rempli de

hydrangea blooms

colorés. Ces plantes vivaces réapparaissent à la fin du printemps et,

selon la variété

, elles peuvent offrir un spectacle époustouflant ou des fleurs luxuriantes tout au long de l’été. Mais pour être sûr d’obtenir le plus de fleurs possible, il faut transplanter les nouveaux hortensias au bon moment.

Heureusement, la fenêtre n’est pas courte, mais il faut connaître les bonnes conditions météorologiques et la bonne saison. Ce calendrier s’applique que vous ayez acheté de nouveaux hortensias pour votre jardin ou que vous souhaitiez déplacer ceux que vous possédez déjà.

Vous voulez prendre de l’avance sur la floraison de l’été prochain ? Voici ce que deux experts ont à dire sur le meilleur moment pour transplanter des hortensias, ainsi que leurs conseils pour une transplantation réussie.



Ce qu’il faut prendre en compte avant de transplanter des hortensias

Si vous transplantez un hortensia à la mauvaise période de l’année, vous risquez de stresser la plante et d’affecter le potentiel de votre prochaine floraison. La plante peut subir un choc de transplantation, ce qui se traduit par des symptômes tels que des feuilles tombantes et

des bourgeons et des fleurs moins nombreux ou inexistants

. Dans de nombreux cas, l’hortensia se rétablit l’année suivante, mais il arrive que le choc de la transplantation marque la fin de la plante.

Pour éviter le choc de la transplantation, le meilleur moment pour transplanter un hortensia est lorsqu’il est en dormance. Cela signifie que les fleurs sont mortes et que la plupart des feuilles sont tombées. Le temps devrait être frais et, idéalement, vous ne serez pas en période de sécheresse, car l’hortensia a besoin d’être arrosé en permanence après avoir été transplanté.

Hydrangeas with pink blooms


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/Getty Images




Best Time To Transplant Hydrangeas

Transplanting hydrangeas during the dormant season typically means either transplanting in the fall, after the hydrangea has begun to die back for the season, or early spring, before it starts its growth season. « In the fall, plants are about to go into their dormant state for the season so they can focus all of their energy on root development instead of top growth, » says Dillon.

This timing will vary by climate but a good rule of thumb is to plant when you feel confident there will be six weeks of mild, cooler temperatures ahead. You want to leave plenty of time for the hydrangea to establish its roots before extreme heat or extreme cold sets in. Aim for planting after the last frost in spring.


Transplant Hydrangeas in Fall

« I grew up with a father who ran a very large garden center. I can still see the banner ‘Fall is for planting,' » says Heider Chapple. She explains that fall is the least stressful time for shrubbery, like hydrangeas, to establish their roots.

Heider Chapple says, « If you are dividing, transplanting, or just establishing new gardens, fall is the time. The hydrangea will not have to go through the heat of the summer as it develops root structure and becomes part of your property. »

To find the exact right timing, wait until the blooms have died and the leaves have turned brown and begun to fall. As long as you’re ahead of the first frost and the ground is still pliable, you’re within the fall planting window. Dillon advises that this is usually six to eight weeks before the first frost.


Transplant Hydrangeas in Spring

Spring is also fair game for transplanting hydrangeas, which is good news for those who are planning their garden a bit more last minute. Wait until the last threat of frost has passed, but don’t push it so far into spring that the hydrangea has already started its rapid growth for summer.

Hydrangea with blooms


blew_i

/Getty Images




How To Transplant Hydrangeas

The key to transplanting hydrangeas is moisture, moisture, and more moisture. You’ll want to keep the soil wet throughout the process.

Here’s the step-by-step guide to transplanting hydrangeas.

  1. Choose the right day for transplanting. « Transplant on a cloudy day. Cloudy days and cooler temperatures will help with transplant shock, » says Dillon.
  2. Select a spot that gets the right amount of light for your type of hydrangea and plenty of moisture. « Although hydrangeas are labeled full sun plants, in Southern climates, they benefit from afternoon shade. Hydrangeas get sunburned easily so some protection from the hottest part of the day will ensure your blooms stay beautiful all season long, » says Dillon.
  3. Dig a hole that is larger than the rootball. Add in organic matter to help drainage and enrich the soil to minimize shock.
  4. Fill the hole with water. Ideally, you want to see that the hole is not draining rapidly. Because hydrangeas love moisture, they do best in an area that will maintain consistent moisture.
  5. Make sure you’ve gotten as much of the root ball as possible when digging up a hydrangea. Water it before transplanting.
  6. Plant the hydrangea in the prepared hole, making sure that it is adequately wet (muddy is good!). Fill in the soil. Water it again. Add a layer of mulch to help seal in the ingredients.

To minimize the risk of transplant shock, there’s one step you can take beyond timing it right. Make sure you dig up as much of the root ball as possible and place it in a hole with plenty of room. Keep it consistently moist.



Caring For Transplanted Hydrangeas

If you want a low maintenance transplant season, go for fall. « Planting in the fall will keep you from having to babysit your hydrangea during the season. You still need to monitor its hydration needs for the first year, but it will be a bit more forgiving if fall planted, » says Dillon.

But regardless of when you transplant your hydrangeas, the number one priority is making sure they stay consistently watered. During the spring, it’s actually easier to monitor since you can watch the leaves for signs that they’re thirsty, like drooping or wilting. It’s slightly more difficult in the fall when you’re looking at dead branches, but you can feel the soil with your finger to make sure it’s moist about an inch down.

Hydrangeas should be fertilized in early spring and fall, regardless of whether they’ve been transplanted.


Frequently Asked Questions


  • Can I transplant hydrangeas during the summer?

    Ideally, you would not transplant a hydrangea during the summer. If it’s absolutely necessary to transplant a hydrangea during the summer, try to find a stretch of days where the weather is unseasonably cool and rainy.


  • How long does it take for transplanted hydrangeas to establish?

    Even if a transplanted hydrangea doesn’t go into transplant shock, it can still take a full year for it to settle in and bloom again.


  • Should I prune hydrangeas before or after transplanting?

    You don’t need to prune hydrangeas to transplant them but, if you do want to cut them back, do so before you transplant.


  • Can I transplant hydrangeas in containers?

    Absolutely! You can and should transplant

    hydrangeas in containers

    and pots as they outgrow one container and need to go to the next size.


  • What are the signs of transplant shock in hydrangeas?

    If your hydrangea is suffering from transplant shock, you’ll notice that its leaves are wilting, turning brown and beginning to drop. Another unfortunate symptom of hydrangea transplant shock is a lack of blooms.