Roses are extremely popular flowers, and hybridizers have been crossing them and selecting them for centuries. As you noted, they come in many forms. Form refers to the plant's use in the landscape. Tree roses have a long stem and a shrubby top. Miniatures grow no more than 18-24 inches tall. Ground cover roses are low growers that may spread up to 8 feet wide. Climbers have arching stems 6-20 feet long. Floribundas have clusters of medium-size blooms. Hybrid teas are the classic cut-flower rose. Grandifloras resemble hybrid teas but develop flowers in clusters. Old garden roses are types that were developed before 1867, when hybrid teas were introduced. Modern shrub roses combine old garden rose flower form and fragrance with recurrent bloom and a broader color range.