The way that this form of metamorphism works is that rocks are scraped against each other causing them to be ground into a powder. Then this powder is reformed due to the pressure in the zone and the heat caused by friction of the two rock surfaces.ocks are classified by the processes under which they were formed. The differences in formation account for variations in the appearance of the rocks and, with some practice, you can learn to recognize the different types by sight. Metamorphic Rocks are rocks that have changed form due to heat and pressure.
Growing 4 to 6 feet in height and width, both mophead and lacecap hydrangeas can be used as specimen plants, in mixed borders or in mass plantings. The mountain hydrangea (H. macrophylla subsp. serrata) is a subspecies of bigleaf hydrangea that has slightly smaller leaves and flowers (see image at right).
Smooth Hydrangea. Smooth hydrangea (H. arborescens), is named for its large, smooth leaves. Sometimes called snowball hydrangea, it grows about 4 feet tall and is hardy in Zones 4â9. Smooth hydrangea can take full sun if the soil stays moist, but part shade is best in most other situations.âAnnabelleâ is the best-known cultivar, with huge flowers in early summer. Flowers start out white, then fade to green and tan. Other cultivars have pink flowers.Smooth hydrangea blooms on new wood (this yearâs growth), so it can be cut to the ground in winter or early spring and still flower the same year. Good to Know: These hydrangeas tend to flop after rain, so support plants with a wire frame to keep them upright and looking their best.igleaf Hydrangea. Among hydrangeas, bigleaf hydrangea (H. macrophylla) may have the showiest flowers of all -- usually in bright hues of pink or blue. Mopheads have big dome-shape flower clusters, while lacecaps have lacy-looking flowerheads featuring a mix of large and small florets.