There are very few plants that can grow under trees that have a dense shade. If you are planning to grow hydrangeas under pine tree, you might wonder if your hydrangea will grow healthy.
Hydrangeas can grow under pine trees under optimal conditions. The Pine canopy should not be too thick and provide dappled sunlight to the hydrangeas.
If the canopy of the pine tree is too dense, it will prevent any sunlight and rainfall from reaching the hydrangeas.
Factors responsible for while growing Hydrangeas under Pine trees
Let us look at the factors that would be responsible for the healthy growth of Hydrangea while it grows under the canopy of Pine trees.
1. Suitable Soil for hydrangeas under pine trees
Here are the attributes required for the soil for Hydrangeas to grow best under Pine trees.
– Soil pH
Pine trees prefer soil that is acidic.
Therefore, the pH of the soil where pine trees grow will naturally be acidic. Not only that, the soil is likely composed of decades of mulch that includes a lot of pine needles that have fallen over the years. These pine needles are also slightly acidic or neutral.
However, as they decompose in the soil, the organic matter that develops is only slightly acidic or even pH neutral.
That is why, although a lot of people believe that pine needles impact the pH of the soil greatly, it is not true. The difference will be slight. Hydrangeas do very well in acidic soil.
If the variety of hydrangea that you have belongs to the species Hydrangea Macrophylla or Bigleaf hydrangea, the flowers will be blue in color.
This is because the color of the hydrangea blooms changes depending on the pH of the soil.
So, if you want pink hydrangeas which need slightly alkaline soil, you will have to increase the pH of the soil by adding lime or wood ash, which are both alkaline in nature.
– Soil structure
The structure of the soil under pine trees may not be the best for growing hydrangeas. However, with a few changes, you can adjust the conditions to be more suitable for hydrangeas.
You will need to add a lot of organic matter to the area of the soil where you are going to plant your hydrangea. It should be at least 6 inches deep and wide enough to accommodate the size of the root system of the plant when it reaches full maturity.
Gardeners use garden compost, leaf mould, or farm manure to mix with the soil. They will all help in retaining moisture in the soil as well as allowing water to flow out freely so that it does not collect around the roots and make the soil water-logged.
This organic material will also help to make the soil more fertile. The pH of the soil will also remain at around 6 to 7.
Organic matter is also essential. One of the reasons that hydrangeas die is that they are not able to soak up sufficient water from the soil.
Adding organic matter will help to maintain the balance of moisture in the soil that hydrangeas need.
– Mulching
If your hydrangea is planted under a pine tree where it is not getting an adequate amount of moisture, regular mulching can help greatly.
Apply a layer of mulch at least 2 inches thick to the soil surrounding your hydrangea. Make sure there is a distance of at least 6 inches between the mulch and the stems of the hydrangea. As hydrangea does not like to be consistently exposed to the moist or wet material.
There are a lot of benefits of mulching around your hydrangea.
- Mulch improves the texture of the soil.
- It retains water in the soil so that it is sufficiently moist for the roots of the plant.
- Mulching also adds nutrients to the soil.
- It stimulates the beneficial ecosystem of the soil.
- Mulching helps prevent the growth of weeds.
You need to add mulch to the soil around your hydrangea immediately after it has been planted. This is because the plant is most prone to drought right after planting.
A lot of materials can be used for mulching, but for dry conditions, the best materials are compost, manure, or leaf mould.
These materials can hold moisture really well, while their structure allows water to drain easily, which is what hydrangeas require.
2. Watering hydrangeas
It is very important to make sure that plants planted under pine trees receive enough water.
Pine trees can prevent other plants from getting an adequate amount of water. Often, the rain gets caught in the canopy of the tree, which means that it does not reach the ground at all.
Not only that, the root system of pine trees is vast and requires a lot of water. The tree can soak up the water from the area, leaving very little for the rest of the plants.
Hydrangeas are also thirsty plants. Therefore, it is essential to water your hydrangeas regularly, especially during the spring and summer seasons when it can get hot and dry.
The best way to maintain and control the optimal amount of water and moisture is to use a soaker hose irrigation system. This will provide the plant with water gradually during the hot summer days.
If an irrigation system is not possible, then you will need to provide your hydrangea with around 2 gallons of water every 2 to 3 days during the growing season. The soil needs to be moist at all times.
You can check the moisture of the soil by pushing your finger up to 1 inch through the soil. If it is dry to the touch, you need to increase the frequency of watering the plant. Increase the frequency to every other day if needed.
It seems like too much water, especially when hydrangeas do not like waterlogged soil. However, you need to remember that the hydrangea competes with the root system of the pine tree for moisture.
Therefore, you need to keep an eye on the moisture level of the soil around your hydrangea and adjust the watering frequency accordingly.
During winter, hydrangea becomes dormant. At this point, it does not need any additional moisture.
3. Light
Hydrangeas need sunlight to grow well. They cannot grow properly in complete shade. Even if they do get established in full shade, they will not be able to bloom and flourish to their potential.
If your hydrangea is under a pine tree that is completely blocking the light from reaching your plant, you may need to remove some of the branches to let light in.
Matured and established pine trees will not face any issue with cutting off some of the branches at any time of the year, but the best time to do so is in winter.
If the pine tree is casting dappled light on your hydrangea through the canopy, it is enough for the hydrangea to grow properly as long as the soil has adequate organic matter.
Most of the hydrangea varieties require the morning sun with partial shade in the afternoon. Some varieties can grow in full sun, but it can also slow down the rate of growth.
Bigleaf hydrangeas grow best in full shade.
4. Fertilizers
If your hydrangea is planted in soil that has a good amount of organic matter and gets mulched once or twice a year, fertilizers are not really necessary.
However, pine trees and hydrangeas both have a vast but shallow root system. Therefore, both have to compete for nutrients in the soil.
Pine trees, having been established for years, often soak up all the nutrients. Therefore, adding fertilizers to the hydrangea plant can be a good idea to ensure that the plant does not lack any nutrients needed to produce blooms.
Hydrangeas are not fussy plants, so you can apply a helping of fertilizer once in spring and then in July to make sure that the plant grows healthy and blooms properly.
If you have soil with poor fertility, you might want to use some special fertilizers.
Granular slow-release fertilizers need to be applied only two times a year. You need to follow the instructions given on the package.
There is not much risk of over-fertilizing your plant as it is a slow-release fertilizer. Over-fertilizing the plant can burn the roots and kill the plant.
Fertilizers should be added along with a good helping of mulch. Mulch helps soak the water while retaining the moisture in the soil. It also adds nutrients to the plant.
The best way to apply granular fertilizer is to move aside the mulch and apply the granules to the soil and then put the mulch back in place on top of the fertilizer.
Do not apply any fertilizers after August, as the plant starts to prepare for dormancy during winters, and adding fertilizers will stimulate new growth.
Best hydrangeas to grow under pine trees
The best variety of hydrangeas to grow under pine trees is Hydrangea Macrophylla, or the Bigleaf hydrangea, as it is commonly called.
There are many varieties in this species of hydrangea which come in different colors. They have large foliage that looks good even when the plant is not in its blooming season.
Bigleaf hydrangeas will flower even in the shade and dappled light, but the flowers will grow much larger and better in a good amount of sunlight.
Attributes required by plants to grow under pine trees
Plants that meet the following requirements can grow well under pine trees:
- Can grow well in acidic soil.
- Do not need much sunlight and can live in shade.
- Require less water.
- Can handle the falling pine needles.
Other plants that grow well under pine trees
- Lily of the Valley
- Wild geraniums
- Rhododendron
- Bleeding hearts
- Columbines
- Jacob’s ladder
- Sweet woodruff
- Creeping Phlox
- Bearberry plants
