You can grow hydrangeas in clay soil, but it is recommended to amend it with sand and old compost to improve drainage ability.
Varieties like Annabelle hydrangea, which are native to North America, can be grown in clay soil.
Prominent for its colour blossoms, hydrangeas can be grown in almost all soil types. These ornamental plants thrive when provided with consistent moisture.
But do hydrangeas like to grow in clay soil, or they prefer sandy soil?
Hydrangea plants enjoy deep watering at regular intervals. But, as a gardener, you should avoid water logging at the root level. Excess water accumulated in the plant pit can result in yellow leaves and root rot.
This flowering plant isn’t too picky about the kind of soil. You can plant and grow hydrangeas in clay soil. However, not all varieties can tolerate soggy soil.
You can improve the drainage ability of your clay soil with soil amendments.
As clay soil is known to hold moisture for a longer time, you should regulate watering frequency accordingly.
To avoid overwatering, it is recommended that you check the moisture of clay soil before watering.
The problem with clay soil is that when not watered, the top layer of the soil dries out. But, the inner layers will be moist. It would help if you didn’t water your hydrangeas by inspecting the top layer of clay soil.
Take a toothpick and insert more than 1 inch into the garden soil. If you find the stick is moist, then hold on. You can water your plant when the clay soil has dried by 1 inch.
Hydrangeas and Soil: What is the best soil?
Massachusetts Amherst State University states that Hydrangea plants prefer well-drained and consistently moist soil that has moderate nutritional levels.
These ornamental plants aren’t drought tolerant and can’t survive in sandy soil.
If you’re growing hydrangeas in heavily compact soil, then unnecessary water logging can result in root rot. Similarly, sandy soil that can’t hold moisture for a long time can result in underwatered hydrangeas.
When it comes to soil, you must consider soil composition, drainage ability and pH to grow hydrangeas.
In some cases, if you’re not looking for different-coloured blossoms, you can ignore pH. Hydrangea plants can grow in alkaline and acidic soil.
With the change in soil pH, the Bigleaf hydrangea plant variety can produce different-coloured flowers.
The soil must be well-drained and should be able to retain moisture for a longer time.
And according to your soil composition, you must reduce watering hydrangeas.
Do Hydrangeas Like Clay Soil?
Compared to other indoor plants, hydrangeas are more open about growing soil.
Not all hydrangea plant varieties like clay soil, but there are a few prominent varieties like Smooth Hydrangea, Climbing Hydrangea and Bigleaf hydrangea plants that can be grown in clay soil.
But, with proper care and soil amendment, even these varieties can survive in clay soil.
Hydrangeas need well-drained soil to be able to drain excess water. If your garden consists of clay soil, you can prepare by adding soil amendments like organic matter to improve soil composition.
Later in this article, I’ll discuss the steps with which you can improve soil texture and draining ability.
Before that, take a look at the required soil pH to grow this ornamental plant.
Hydrangeas and Clay Soil pH
The ideal soil pH to successfully grow hydrangeas ranges from 5.2 to 5.5. However, whatever can be the soil pH, hydrangeas will grow.
Depending on acidic soil, alkaline or neutral soil pH, hydrangea blooms different coloured flowers.
If the soil is acidic, then you can expect blue blossoms. Similarly, pink and white coloured flowers appear when the pH is alkaline or neutral.
Anyway, it takes months to see different coloured flowers.
Though most clay soil is alkaline in nature, there can be acidic soil. You must conduct a soil test to determine the pH.
Hydrangea varieties like endless summer hydrangeas can be grown in loamy soil (clay soil with sand).
Check this: Do Hydrangeas Repel or Attract Mosquitoes?
Clay Soil Amendment: How to Improve?
When clay becomes dry, it turns rock hard. Wet clay soil will be sticky, and you can’t even walk with your shoes in the garden.
Having finely textured clay soil is one of the biggest challenges for home gardeners.
Along with the cons, clay soil has its advantages. Linda Brewer from the Department of Soil Science says this soil can hold nutrients, pesticides and fertilizers effectively.
Further, Brewer says you can improve the texture of clay soil by adding organic material.
For instance, sawdust, manure, leaf mold, peat moss, compost and bark are a few organic soil amendments that improve the drainage ability of your clay soil.
Dug 6 inches of clay soil into your garden bed and add 2-3 inches of organic matter (leaf mold, manure or compost). Rototill the soil mixture, or you can use a fork to till the soil.
Note: Don’t add sand to clay soil to improve its texture. The largest clay particle is 1000 times smaller when compared with the smallest sand particle. If you add sand with clay soil and expect to do wonders, then you’ll have to deal with more difficult soil.
Microorganisms in the soil will break down organic matter, eventually releasing nutrients into the soil.
At regular intervals, you must keep on adding organic matter to the soil. This addition will help to keep the soil porous and well-drained.
Important Tip: You can just add compost to clay soil to improve its texture. Raised garden beds are a big saver for clay soil gardeners.
Also Read: Can You Mix Epsom Salt With Fertilizer?
How to Plant Hydrangeas in Clay Soil?
You can either dig a hole, add soil amendments to it and grow plants or just plan raised garden beds filled with high-quality soil.
Building raised gardening beds can be time-consuming and expensive. However, your clay garden soil problem will have a quick solution.
1. Dig a hole that is 2-3 times deeper and wider than the hydrangea root ball.
2. Add prepared soil amendment to the hole and plant your hydrangea.
3. As mentioned, you can add well-rotted manure or lead mold to clay soil and put it in the hole. Remember, organic material should be not more than 10 per cent of clay soil.
4. Now, cover the surface of the soil with sawdust, bark and ground wood chips. These materials will also act as mulch and, with time, will decompose into the soil.
While planting in clay soil, choose a sunny spot, as the fine texture of clay soil can hold moisture for a longer time; exposing it to full sun will allow the evaporation of extra moisture into the atmosphere.
Don’t choose a low-lying spot to plant your hydrangea plant. With heavy rains, all the water in the garden accumulates in your plant pit.
This gardener created a new garden bed for clay soil; it’s worth having a look.
Check this out: Are eggshells good for hydrangeas?
Building Raised Garden Beds in Clay Soil
It is one of the most effective ways to put a full stop to all your clay soil gardening problems.
Caution: It can be expensive to build raised garden beds.
- Choose a spot that gets enough sunlight—hydrangeas like to grow in partial sun.
- The first step is going to be removing the turf. This will remove weeds or grassroots from the garden.
- Dig 2-3 inches down the clay soil; this will avoid any weed growth in the garden bed.
- You can use pipe boards, wooden blocks or any other hard material to build your raised garden bed.
- Spread 2 inches of mountain granite; this will help with drainage of your raised bed and avoid weed growth. Instead, you can also spread organic material like straw grass or bark.
- Now, fill the raised garden bed with quality soil bought from the store.
- Plant hydrangeas and cover the plant with organic mulch.
How Much Water Hydrangeas in Clay Soil Need?
Clay soil, with its fine soil texture, is known to hold moisture for a longer time. So, you can reduce the watering frequency of hydrangeas in clay soil.
As mentioned above, the top layer of clay soil may look dry, but the inner layers of the soil can be moist.
To avoid overwatering or underwatering, you must inspect the moisture by inserting a stick more than 1 inch into the soil.
Deep water the plant if you find the soil is sticky.
Water hydrangea plant once in 10 days; you can increase or decrease based on the climatic conditions in your region.
How Mulching Benefits Hydrangeas in Clay Soil?
Cover hydrangea plants with organic material like bark and leaf mold; this will act as mulch and preserve moisture. Also, with time, this mulch will be decomposed to add nutrients to growing soil.
As the top layer of clay soil dries quickly, mulching will avoid this problem.
Mulching with hay grass or other organic material will regulate temperature and reduce moisture escape into the atmosphere.
While mulching, make sure to leave one inch of gap between the stem of the hydrangea plant and the mulch; constant moisture will lead to stem rot.
Hydrangeas Colour in Clay Soil
Most clay soils are alkaline, so your hydrangeas bloom pink flowers.
For a change in colour, you can acidify the soil by adding compost or using elemental sulfur and aluminium.
With lower pH, the hydrangea plant produces blue-coloured flowers.
However, the change will take time. It may take months to produce new coloured blossoms.
Hydrangeas Plant Care Tips
Below listed are tips that ensure your hydrangeas do well in clay soil.
- Choose the right hydrangeas that do well in clay soil: Hydrangea like Hydrangea macrophylla (bigleaf hydrangea) and Hydrangea quercifolia (oakleaf hydrangea) tend to thrive in clay soil conditions.
- Prepare the soil by mixing sand and old compost: Before planting hydrangeas in clay soil, it’s essential to amend it. Mix in organic matter like compost or well-rotted manure to improve drainage and increase the soil’s ability to retain moisture and avoid water logging.
- Planting Depth: Dig a hole for your hydrangea that’s about two times as wide as the root ball but not much deeper. Planting too deep can lead to poor growth. Ensure that the top of the root ball is level with the surrounding soil.
- Mulching: Apply a layer of organic mulch around the base of the hydrangea to help retain soil moisture, regulate soil temperature, and prevent weeds. Wood chips or shredded leaves work well as mulch.
- Clay soil retains moisture better than sandy soil, so you’ll need to water your hydrangeas less frequently. However, make sure the soil stays consistently moist but not soggy. Hydrangeas generally prefer deep, thorough watering rather than shallow, frequent watering.
- Fertilizing: Hydrangeas benefit from regular feeding during the growing season. Use a balanced, slow-release fertilizer or a specialized hydrangea fertilizer according to the package instructions. Avoid excessive nitrogen, as it can promote lush foliage at the expense of flowers.
- Pruning: Prune your hydrangeas at the appropriate time for their specific variety. For example, prune Hydrangea macrophylla types after they bloom, as they set flower buds on old wood. Oakleaf hydrangeas can be pruned in late winter or early spring.
- Sunlight: While hydrangeas can tolerate some shade, they generally thrive in partial sun to full sun. Ensure they receive at least 4-6 hours of sunlight daily for optimal flowering.
- Protection from Frost: In areas with harsh winters, protect your hydrangeas from frost damage by covering them with burlap or providing a layer of mulch over the root zone.
- Monitor pH Levels: The colour of hydrangea flowers can be affected by the pH level of the soil. For blue flowers, maintain an acidic soil pH (around 5.5), while for pink flowers, a more alkaline pH (above 6.0) is preferable.
- Winter Mulch: In cold climates, consider applying a layer of mulch around the base of your hydrangeas in late fall to insulate the roots and protect them from freezing temperatures.
Hydrangeas can be grown in clay soil.
But, you must mix soil amendments with organic material like bark leaves, compost or leaf mould—earthworms in the soil help to decompose this organic material and add nutrients to the soil.
Regular addition of organic material to clay soil will improve its ability to drain.
By this, can you conclude hydrangeas are like clay soil?
As said, this ornamental plant is open to soil. It just needs consistent moist and well-drained soil to avoid water logging.
Otherwise, you can just build a raised garden bed on your clay soil. This might be expensive, but you’ll not have to work regularly around the garden.
Khaja Moinuddin, a computer science graduate, finds joy in gardening and homesteading. Join him on this blog as he shares his experiences in homesteading, gardening, and composting