Why isn’t my shrub flowering?

We trust a shrub to provide us an abundance of blooms, so when it doesn’t, we wonder why. There are plenty of explanations! Let’s run through the possibilities to see if any of them fit your situation. After you identify the issue, we’ll list a solution. 

Problem - Planting is too new.

New plants will behave a bit differently than those that are established and have been growing in the garden for a few years. Essentially they are working hard to grow their root system out into the new environment. (A healthy root system is vital to a plant’s good health, as it supports the existing foliage and helps the plant make more). It’s not uncommon for a shrub not to grow much or bloom after it is newly planted.

Double Play Doozie Spirea in a Proven Winners ColorChoice pot next to a shovel in a garden

Solution - Time.

Your plant will become established with time. When given proper access to sunlight and the right amount of moisture, it will grow a root system. Usually the shrub will be able to devote energy to producing flowers after a year or so.

Problem - Not enough sun exposure.

Almost every shrub needs a minimum of four hours of direct light to have energy to produce flower buds. Some shrubs need a minimum of six hours. Check the plant’s tag or the online profile to see what its light preferences are. If you look out your window a few times a day, you should get a good idea of roughly how many hours the plant is getting.

Solution - Transplant.

You can transplant your shrub to a sunnier spot. Learn more about that in this article.

Problem - Spring temperature snap.

If your shrub is supposed to bloom in the spring OR grows its flower buds on old wood, it’s possible that a springtime shift in temperatures killed that growth on your plant. This is the most common with bigleaf hydrangeas, as the flower buds are pretty sensitive. You’ll be able to tell if your shrub was harmed by a frost right after it happens. Your plant was zapped if the buds were previously bright green and plump, but they’re black and shriveled instead. However, if spring was many weeks or months in the past, it’s hard to tell if it was damaged by frost.

Solution - Prepare for next year.

There’s nothing you can do about the current growing season, but you can prepare to get flowers the next year. Plan to keep an eye on this sensitive shrub in the late winter/early spring. If you notice swelling buds, prepare to cover it with a sheet if nighttime frosts are predicted. This will keep the extreme cold from settling onto that sensitive plant tissue. You can remove the sheet during the day when the temperatures warm back up.

Problem - Pruning mishap.

Pruning can be a bit tricky to understand. One big factor in pruning a shrub is to know whether it blooms on old or new wood. Shrubs that bloom on old wood shouldn’t be pruned before they flower, as this removes said flowers. Shrubs that bloom on new wood shouldn’t be pruned too late in the growing season, as they may have already started to develop their buds.

Close up of a pruned shrub

Solution - Wait for new growth.

You can’t unprune a plant, unfortunately. So the only thing that will help is the passage of time. Keep the plant growing happily and it will bloom again in the future.

Problem - Stress from a watering issue.

Both over- and under-watering cause a plant to get stressed. New plants like moist but not soggy soil. If plants are consistently over-watered, they’ll get root rot. If plants are consistently under-watered, they’ll get crispy, fail to perform well, and may even die. Established plants usually only need water when there is a break in consistent precipitation. 

Solution - Monitor closely.

In the ground, a plant will get established faster and perform better long term if you water deeply when the soil is dry or almost dry. (This method is much easier on both the plant and the gardener than frequently watering just a little all the time.) Less frequent, deep watering encourages the plant to grow its roots outward in search of water. All bets are off for a container though. The soil dries out faster so the shrubs will need more attention. Some regions may even require daily watering.

Problem - Animal browsing.

If you’re seeing irregular rip marks in the foliage, you’ve likely got an animal sampling your plants. Deer and rabbits are the most common suspects. While these animals nibble away on foliage, they can also remove flower buds from your plant and prevent it from blooming.

Solution - Build a plan.

Apply a deterrent to the area based on your guess as to what’s bothering the plant. Or transplant it to a more protected spot that would be hard for the pest to get to. OR plant things around it that may make it smell worse to deer. The last method only has a chance of working if there are a lot of other options for the deer to eat from. Like a nearby forest or park.

Problem - Incorrect planting depth.

Plants need to have their rootballs positioned at or just above the soil line. If they are planted too deeply, they’ll struggle in many different ways, including the inability to produce as many flowers. You’ll want to see their roots just under the soil surface.

Close up of the base of a hydrangea

Solution - Reposition/replant.

If the roots are a bit exposed, cover them with soil. If they’re extremely exposed, consider replanting the shrub a bit deeper. Or the opposite problem, if you dig down and see that many of the stems are buried, you should dig the plant up and reposition it so the roots are just below the soil surface. Add a layer of mulch over the top of the soil to insulate the roots from temperature swings. Be sure that the mulch isn’t touching any of the stems.

Problem - Too much fertilizer.

If fertilizer is applied more than twice in a season, it could encourage the shrub to produce more foliage than flowers. This can easily happen if a shrub receives the same water as annuals, which may have a water-soluble formula added to it. It also unknowingly occurs when lawn fertilizer is spread a bit too freely. 

Solution - Stop fertilizing.

You’ll want to stop applying fertilizer for the current season, at least, and likely the following year so the fertilizer that is present can work its way into the soil. Contrary to our expectations, most shrubs will thrive with the nutrients that are already available in the soil. As always, there are exceptions. Like when the soil is particularly poor or you have a very heavy feeder like a rose.

Problem - Nutrient deficiency.

This is a common problem for shrubs in containers. They run through the available nutrients in a few seasons. They either need an application of fertilizer or to be repotted into a larger container with new soil. In terms of plants in the ground, nutrient deficiency is more likely to affect shrubs in poor or sandy soil.

Solution - Fertilize and supplement.

Either get a soil test performed to see what the exact makeup of your soil is, or think back to your garden’s history. When’s the last time you fertilized? Ever? If needed, apply a granular fertilizer formulated for flowering shrubs. Follow the instructions on the packaging. You could also use some compost and apply that to the soil surface and work it into the native soil. Apply fertilizer in the spring and, if you’d like, again in early summer. Be sure not to fertilize after mid-July.

Problem - Other environmental stress factors.

Some other common plant problems are the bathtub effect or issues arising from the use of landscape fabric. These two things stress a plant out enough so that it may not have the energy to produce flowers.

Solution - Remove the problem.

If either of these situations applies to your garden, get ready to do a little manual labor to fix the situation. 

Bath tub effect

  1. Dig up your plant. 
  2. Get a shovel or garden fork and mix the non-native soil in with the surrounding soil. Go a few feet in all directions.
  3. Replant your shrub, filling in the hole with a mix of the non-native and native soils.

Landscape fabric

  1. If there’s mulch on top of your fabric, move it far away from the plant and expose a large area of fabric. 
  2. Cut out the fabric from around the plant so that it is not covering any of the soil surface above the rootball.
  3. Put the mulch back in place, including over the bare ground near the shrub. 

If none of these problems seem to apply to you, feel free to submit photos of your garden and a description of your plant’s care and growing conditions here. We can help you figure out why your shrub isn’t flowering!

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Picture of Kristina Howley

Kristina Howley

I am all in when it comes to gardening. Almost every part of the experience delights me – new leaves emerging in spring, pollinators buzzing in summer, birds devouring berries in fall, and the somber beauty of seed heads in winter. Thanks to a background in horticulture and gardening my own clay-filled, flowery USDA zone 5b plot, I’ve learned plenty of practical things as well. I like sharing these joys and lessons with my fellow gardeners and soon-to-be gardeners any way I can.

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