Gardening With Hydrangeas

A common complaint among gardener is that late in the summer, before the fall foliage, there seems to be lull in garden color.  There is, however, no shortage of shrubs which bloom in later in the season.  Hydrangeas are one the most versatile.  In fact, they are indispensable in the garden for summer color and foliage texture.  No shrub border is complete without them.   

Hydrangeas prefer part shade and rich organic soil.  They prefer morning sun with afternoon shade; this will protect them from the hottest part of the day. If they get shade in the morning and sun in the afternoon they may look stressed due to the sudden rise in temperature.  Hydrangeas need lots of water especially young plants since they tend to dry out quickly during the hot weather.  After planting be sure to mulch well, this will help the soil retain moisture as well as help prevent weeds from encroaching on your garden.  Fertilize the shrubs in the spring and then again in late summer.  Adding compost to the soil around the base of the hydrangea each spring will keep the soil rich.

Lacecap and Nnikko Blue Hydrangeas are both cultivars of (Hydrangea macrophyllla). Lacecaps are recognized by its ring of flowers surrounding a center of florets and nikko blue by it large pom-pom like flowers.  You can change the color of the blossoms of these varieties by changing the acidity of the soil.  Add aluminum sulfate to make the soil acid.  A pH level somewhere between 5 and 5.5 will result in blue flowers. Alternately, for pink flowers, make raise the pH level to 6.0 by adding lime, making the soil alkaline. You will need to repeat the this 2 or 3 times over the growing season and continue the process for as long as you want the change to continue.

The large (up to 15” long) white flowers of the PeeGee Hydrangea (Hydrangea paniculta) turn to a faded pink in the fall and are great for cutting and taking indoors.  Because their large flowers often weigh down its stems, PeeGee hydrangeas require staking. 

Oak Leaf Hydrangea (Hydrangea quercifolia) has a much different appearance than the other hydrangeas.  Its foliage resembles that of the American oak.  Its white blooms fade to pink in fall.   Oakleaf hydrangeas grow to about 6’ and can tolerate more shade than other hydrangeas.

Climbing Hydrangea (Hydrangea petiolaris) is a deciduous vine which clings to garden structures, walls and fences with aerial roots.  Its flowers are white and have the characteristics of the lacecap hydrangea. 

Though there are numerous choices when it comes to types of hydrangeas, there are some general rules of thumb to follow when planting and caring for them.   When planting new hydrangeas you'll need to add a mix of compost and peat moss to the existing soil.  This will give the plant plenty of nutrients and the soil ability to retain water.  Dig a hole approximately twice as wide as the root ball and just as deep.  Place the hydrangea in the hole, making sure the top of the root ball matches the existing grade of the garden.  Never install any plant below grade, its often detrimental to the health of the plant.  Backfill about half way and water to remove air pockets.  Finish filling the hole, water again and mulch.  Planting in the spring or fall is best as the hot summer weather can stress hydrangeas.

You can propagate from softwood cuttings in June. Take a 6”-8” tip cutting, strip off the bottom leaves, dip end in rooting hormone, then stick about one inch deep in sterile moist sand, vermiculite or sphagnum moss. Create a mini green house over plants with plastic and place in bright light, not full sun, until roots form. Or, you can just root them in water. Again, place in bright light away from full sun until the roots form.

Pruning hydrangea can be tricky. In the spring prune broken branches and old flower blooms from the previous season.  Don’t cut new shoots; they are where the new blooms will be. In late summer, after blooming, prune to just above the next outward facing bud. For larger flower clusters, thin plant down to half the number of stems.

Noted for their long lasting, late blooming flowers and their unique foliage, hydrangeas are one of the most versatile shrubs in the garden.  Whether among a shrub border, climbing a garden structure or planted on its own as a specimen shrub hydrangeas are a wonderful addition to any garden.

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