5. Daffodil Hill

Hybrid Oak (Quercus x hawkinsii)

Hiya, Hybrid!

Plant hybridization may sound very technical, but it often occurs spontaneously in nature. Oak trees are wind pollinated; their pollen is carried by air and can thus travel to other oak trees. The genetic materials of different oak species are similar enough that sometimes fertilization takes place when pollen from one species is blown to an oak of a different species. The tree that grows from the resulting seed will have traits from each of its parents but will itself be a new species, just like the hybrid oak here.

An arborist at BBG took this photo while climbing high among the oak's branches. (Photo by Chris Roddick)

Keeping Up Appearances

Oaks have been a symbol of strength since ancient times, but even these titans of the forest need some help as they age. This mature hybrid oak is maintained throughout the year. High in the tree's canopy are cables wiring some of its branches together. BBG arborists have installed these cables to help the tree bear the substantial weight of its limbs and to alleviate stress on weakened branches. Gardeners mind the health of the tree's underground roots by not altering the landscape beneath the oak drastically. Even digging too deeply around the tree's base could cause damaging change to the tree's soil, its main source of nutrients.

Notable Neighbors:

• 5A. London plane tree (Platanus x acerifolia)
• 5B. Lacebark pine (Pinus bungeana)
• 5C. Giant sequoia (Sequoiadendron giganteum)
• 5D. Cedar of Lebanon (Cedrus libani)
• 5E. Tulip tree (Liriodendron tulipifera)

Acorns, the fruit of the oak tree, vary in shape and color depending on species. These nuts are a source of food for wildlife—and they were a staple of the ancient Greek diet. Even today, some Native American tribes use acorns in soups, breads, and beverages. (Photo by Daniel Towsey)

There are 300 feet of cable holding up the branches of this hybrid oak. (Photo by Medi Blum)