[Hydrangea Care] When And How To Prune Hydrangeas | Gardening 101
- Pruning shears
- Rooting hormone
- Plant pot
Their gorgeous globular shape and soothing colour make hydrangeas the showstopper in any garden (not to mention a stunning flower arrangement in a vase). Given the right climate and soil conditions, these flowering shrubs can grow up to 15 feet. They start flowering in spring and can continue to bloom right through summer, making them an excellent choice for the foundation of an outdoor garden. Hydrangeas come in a few varieties (oakleaf, French, lace cap, smooth, mophead, etc.) and colours (blue, pink, white). Although they seem to be high-maintenance plants, they are relatively easy to grow and maintain once you know how to care for them. Here, I will share a few tips on pruning hydrangeas, including when and how to do so, besides sharing a few tips on caring for them.
Interesting fact – Hydrangea blooms can change colour depending on the acidity in the soil. In alkaline soil, the blooms are pink whereas they are blue in acidic soil. Sometimes, a single plant can have blooms of different colours due to its roots growing in soils with different pH.
You can also grow hydrangeas in pots on a balcony or terrace, but choose a large pot that allows the roots to spread. The pot should also have a drainage hole.
Step 1: When to prune hydrangeas
While you can prune your hydrangea plant all around the year, it’s best to prune it during the summer after it finishes flowering. For regions where the plant blooms throughout the year, you can choose when to prune it depending on when you want it to bloom. For spring blooms, prune the plant in fall. For fall blooms, prune it in early spring.
Step 2: How to take cuttings from hydrangeas
If you want to propagate new hydrangea plants from cuttings, you should take cuttings only from stems that are at least 8cm long with around 4-6 small leaves. Cut the stem just below the last pair of leaves.
Step 3: Preparing the hydrangea stem for propagation
You should remove all the leaves from the lower part of the stem, leaving only the top ones.
Step 4: Add rooting hormone
Dip the cut stem in rooting hormone to help the plant develop strong and healthy roots.
Step 5: Plant the hydrangea cutting
Place the cut stem in a pot with soil, ensuring that around 5cm of the stem is under the soil. Press lightly around the stem to compact the soil. Place the pot with the cutting in an area with partial shade and water it frequently for keeping the soil moist without overwatering it. In approximately 3 weeks, the cutting would have developed roots and be ready to transplant into the garden or a bigger pot (at least 18 inches diameter). When planting hydrangeas in the garden, choose a suitable spot where the plants can enjoy the morning sun. Avoid planting them directly under trees as they will have to compete for nutrition and water. Popular places for planting hydrangeas are in beds near fences or houses as they can get sunlight in the mornings and shade in the afternoons. Do not plant them in areas where they are exposed to the harsh afternoon sun. Similarly, avoid planting hydrangeas in full shade as they will not bloom.
Step 6: Hydrangea care tips
Hydrangeas do well in soil rich in organic matter, so fertilise them at least twice a year. They require regular watering and well-draining soil. Although they thrive in well-watered soil, you should take care not to overwater the soil. Also, if the soil has poor drainage, the waterlogging can cause the roots to rot. If the soil in your garden or pot is not well-drained, consider adding a lot of compost (even homemade compost from your kitchen waste will work) to improve the soil quality. Underwatering hydrangea can cause the leaves to turn brown. In hot weather, you can help the plant retain moisture by adding mulch to the flower bed. It’s best to water hydrangea plants in the morning with a hose with a spray nozzle so that the leaves have enough time to dry.
If you want to control the colour of hydrangea blooms, you can adjust the soil's pH. Low pH allows the plant to absorb aluminium, resulting in a lovely blue colour. You can add peat moss or sulphur to reduce the pH of the soil in the bed or pot. Some gardeners also add aluminium sulphate to the soil throughout the growing season to get blue blooms. For pink blooms, you need to increase the alkalinity of the soil. One way to achieve this is by adding limestone to the soil.
While hydrangeas are relatively pest and disease-free, they might be infested by slugs, aphids, beetles, and or fruit worms on occasion. Usually, a light spray of soap solution or insecticide will stem the infestation. The plant can also be affected by black spots (usually due to extra-humid conditions or overwatering), powdery mildew and rust. For powdery mildew, you can remove the affected leaves and spray the plant with neem oil diluted with a soap solution and water. For a mild attack of rust, pruning the affected leaves and stems will suffice. In the case of a severe attack, spray with a rust-specific fungicide (organic).
Step 7: How to prune hydrangeas in the fall
For having hydrangea blooms in your spring and summer garden landscape, fall is the best time to prune hydrangea shrubs. You can cut the stems back quite a bit by trimming them around 10cm from the ground. Leave the new growth with buds and prune the deadwood or weak growth.
Note: Not all varieties of hydrangeas are suitable for pruning in the fall as you may end up damaging the plant. When in doubt, you can ask an expert gardener or landscaper for advice.