We've all heard variations of the saying: Tall oaks from tiny acorns grow.

The oak tree family is one where many members flourish. In fact, there are some 80 species of oak growing in North America, 60 of them full-fledged trees, according to Hugh Johnson in his International Book of Trees.

Avid gardeners would be wise to consider adding one or two of the trees to their repertoire, if for no other reason than the shade they produce.

However, there are other good reasons to consider planting an oak, including the fact that the shade produced helps plants that thrive in those conditions.

The oak leaf, being acidic, also helps acid-loving plants such as rhododendrons.

In northern climates, the two most important groups of oak are the white and scarlet groups, typically found in native woodlands and which grow well in hardy conditions.

In the white oak group, trees have lobed leaves with rounded tips, often widest toward the top. Acorns from the group mature in one summer and are then shed by the tree to germinate in the fall. The inside of the cup (in which the acorn sits) is shiny.

A white oak can live for 400 years and grow up to 90 feet tall. It is a species that has a rich heritage, with many early American sailing ships having been built from white oak. Settlers used white oak for their bridges, barns and wagons and the wood is also suitable for barrels, kegs and buckets.

White oak, however, typically does not survive well in city conditions, with those that are preserved in new housing developments frequently declining and dying.

Bur, or mossycup, oak is also native to eastern forests but spreads farther west. A smaller tree, it is more tolerant of a variety of soil conditions and will grow on dry, sandy, alkaline or clay soils as well as richer most ones.

The chestnut oak, named for the similarity of its leaves to those of the American chestnut, is also known as the basket oak because its branches split easily and can be used for weaving. The tree grows up to 50 to 60 feet tall and wide and although it can grow in dry, stony soil, it loves moisture.

The swamp white oak is found growing along stream banks and in wet meadows in the wild. It is surprisingly drought resistant, however, and grows well in drier locations, making it a good choice for larger gardens with acidic soil.

Scarlet oaks, characterized by leaves with pointed lobes and tipped with a bristle, has acorns that take two years to mature. They are shed in the fall but don't germinate until the following spring. The tree is drought-tolerant and grows well in acidic soil. In fact, if it is planted in neutral to alkaline soil, it does not grow as well.

The pin oak, named for its use for doweling pins for fastening barn beams, is widely planted due to its narrower growth habit and ease of transplanting (thanks to a fibrous root system). The tree also loves acidic conditions but tolerates wetter conditions as well.

The northern red oak is a fast-growing species and can live up to 150 years, reaching more than 75 feet in height. It is easily transplanted and withstands city conditions.

The English oak is one more suitable for parks than the average property but a widely available upright form ("Fastigiata") grows only to a height of 60 feet and 15 feet wide, making it suitable for most gardens.

Finally, the shingle oak, named for its ease of splitting into roof shingles, is a member of the willow-leafed group. It transplants easily, is tolerant of most soils except the most dry and retains its leaves all winter.