HYDRANGEA. The Americas, East Asia. Ornamental shrubs of many shapes and sizes. They have large, variously toothed, often shiny leaves, mostly deciduous in winter. The flowers can be small individually but are carried in branched, sometimes massive clusters. An interesting feature in several species is the presence of a ring of larger sterile flowers surrounding a group of smaller, fertile flowers, giving the impression of a lace doily. Most species thrive in sun or light shade near the coast. Some shading may be desirable inland. Ordinary soils, regular watering and fertilizing. The following are hardy to 0^oF or less, except as noted.

macrophylla. These are the typical garden hydrangeas. They are of moderate size, growing 4-8’ tall and rounded in form. Most are rather widely branched, with heavy, somewhat awkward stems. However, these are well concealed from spring to fall by broad, shiny, deeply veined leaves usually 6-10" long. Two types of flower clusters are represented in the modern hybrids: the lace cap form, described above for the genus, and one made up mostly or entirely of the larger, flatter sterile flowers, often referred to as the mop head type. The overall clusters of some selections are truly monstrous, bowing over the branches which carry them and giving the plants a bedraggled look. Pruning the plants to force rebranching reduces this problem and yields shapelier plants. An interesting feature is the response of flower color to the pH of the soil. Flowers which are pink in neutral or slightly alkaline soil (more than slight alkalinity makes the plants chlorotic) turn blue or lavender in acid soil, though different selections respond to different degrees. Hardy to below 0^oF.

Some notable lace cap hybrids include the following.

‘Geoffrey Chadbund’ is a rather dwarf plant with deep purplish rose to purple flower clusters. Often there is a bicolored presentation of purple fertile flowers ringed by reddish sterile flowers.

‘Lemon Wave’. One of the more recent introductions, with cream, bright yellow and light green variegation on a deeper green background. The flower clusters are large, pale in color and tinged with lilac.

‘Mariesii’ is a robust old-fashioned selection, growing easily 6’ high, with rather pale pink to blue flowers.

‘Mariesii Variegata’ is nearly identical to the original ‘Mariesii’ except for cream-variegated leaves.

‘Pink Lace’. A more recent selection, similar to ‘Mariesii’ but distinguished by  larger and brighter pink flower clusters.

‘Teller Red’ is a lower, more spreading plant with huge clusters of purplish red flowers. The fertile flowers are ringed by a double row of very large sterile flowers.

There are so many mop head hydrangeas that any particular array of them is necessarily somewhat arbitrary. Here are some of the more interesting.

’Domotoi’ is one of the larger cultivars, unusual for its full clusters of semidouble pink to blue flowers.

‘Glowing Embers’ is a truly dwarf (2-3’), compact, smaller leaved plant with smallish clusters of vivid red flowers.

‘Merritt Supreme’ is a robust plant producing an abundance of broad carmine “mops”.

‘Nigra’. A compact, tidy plant notable for its nearly jet black stems and deep green, purple tinged leaves. The flowers are purplish rose in color.

‘Pia’ is even smaller than ‘Glowing Embers’, with rather narrow leaves, only 2-3” long. The flowers are borne in small clusters and colored deep rose pink.

‘Sister Therese’ is a robust plant with large clusters of white, single flowers. It is best when grown in light shade, since the flowers are easily browned by the sun during summer heat waves.

paniculata. H. paniculata is one of the larger species, potentially even a small tree. It has pleasant but undistinguished 3-6" leaves, coloring well in the fall. However, it makes a spectacular show of white flowers, in pyramidal clusters in summer. Those of the more commonly grown cultivar ‘Grandiflora’, nicknamed PeeGee hydrangea, are often 1’ or more long. The selection we received several years ago as  ‘Webb’s’ is a more compact, tidy shrub with bright green 2-3" leaves. The flower clusters seem a little smaller than those of ‘Grandiflora’.