Hydrangea

Hydrangeas types

It's almost impossible to imagine a garden without hydrangeas. Hydrangeas are known for their long-lasting, abundant flowers. Most hydrangeas bloom for 2–3 months (from July to September) and some flowers can be up to 30 cm in diameter! There are about 70 or 80 different types of hydrangeas. The most well-known type of hydrangea is the French hydrangea, originating in French Normandy and Brittany. The French hydrangea or Hydrangea macrophylla can be recognised by the coloured balls of flowers. Other popular hydrangeas include the panicled hydrangea, the climbing hydrangea and the Annabelle hydrangea. The flower clusters of the panicled hydrangea are a bit smaller and more pointed than those of the French hydrangea. Climbing hydrangeas are incredibly popular ramblers. The climbing hydrangea is perfect on a wall or pergola. The climbing hydrangea can attach itself but needs a little help at first. The Annabelle hydrangea (Hydrangea arborescens) is known for its stunning, large ball of flowers as well as its white colour. It blooms gorgeously between June and August. Every year, new shoots appear to produce these white flowers.

Hydrangea colours

Hydrangeas actually have only little flowers. The colour we see are actually the bracts. The bracts of some types are liable to become to discoloured. White flowers can change to pink or dark red. A blue hydrangea can also become pink due to the acidity and iron level in the earth. To achieve blue hydrangea flowers, add some potassium to the soil and don't fertilise much. Proper watering is crucial to maintaining their blue colour. Rainwater is the best. A rain barrel can be really convenient to have a water supply during dry spells.

Planting hydrangeas

The hydrangea is an easy shrub and does well in open ground as well as a large flower pot. We always make sure that the soil is sufficiently moist, especially if the hydrangea is in a sunny place. Before you plant the hydrangea, dunk it for a while in a bucket full of lukewarm water to get the root ball nice and wet. The minimum planting distance between hydrangeas or between a hydrangea and other plants is 75-100 cm. Dig a large hole for the plant and put the hydrangea in it. The top of the root ball should be just below ground level. Then fill the hole or pot with a mixture of soil and compost and tamp it down firmly. We always use fresh potting soil. This contains about 60 days of food and the roots of the plant can develop well. Give the plant water straight after putting it in the ground. Climbing hydrangeas need a wall or pergola for support. Then mulch the hydrangea every winter or early spring with a layer of compost mulch and fertiliser. Protect the hydrangea if there is late frost at night by temporarily draping horticultural fleece or bubble wrap so the new buds don't freeze.

Pruning hydrangeas

Before pruning the hydrangea, first check if the shrub is blooming on new or old wood. New wood means this hydrangea blooms every year from new shoots. You can cut the old branches off. Old wood means new buds grow on the same branches.

• Hydrangea types that bloom on new wood can be pruned in the spring. Cut all the branches in early spring back to a few buds from the ground. You can also keep some old branches, cutting them back to about 30 cm above the ground. Or cut off a third of the old branches every year. The hydrangea will flower again the same year. Do be a bit careful with young plants, taking care that their thin branches can bear the weight of heavy flowers.
• We don't prune the types of hydrangeas that bloom on old wood all the way back. These hydrangeas are already producing buds for next year by the end of summer. If these branches are cut off, the shrub won't have any flowers the next year. Just cut off the dead flowers and a bit of the stem in the spring. We always cut the stem back to the first new bud on the branch. Do you need to keep your hydrangeas compact or to rejuvenate it? Then cut back half of the branches in early April and the other half of the branches the next year. That way, the hydrangea will still have flowers every year. This is the case for most French hydrangeas. Be aware that some French hydrangeas grow on new wood. Always read the information on the plant label carefully.

Click this link for more information about pruning hydrangeas.
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