Wednesday, July 28, 2010

Is that a bonsai?

Frequently horticulture staff and volunteers hear visitors ask a lot of the same questions. Today we will answer one of the questions heard frequently in the Japanese garden.

A lot of visitors ask if the short scotch pine in the Japanese garden are bonsai. Although the conservatory houses a large collection of bonsai, there are no bonsai in the Japanese garden. The trees in the Japanese garden have some similarities to bonsai but one obvious difference. Bonsai trees are grown in pots, whereas Japanese garden trees are grown in the landscape. Trees in Japanese gardens are pruned similar to bonsai but the root growth is not restricted resulting in larger trees of a similar style to bonsai.

The scotch pine and mugho pine in the Japanese garden are pruned similarly. In spring the new growth or candles on the trees are shortened to reduce growth and stimulate the development of buds on the trees for future growth. The trees are otherwise pruned to remove verticle growth within the pads of foliage to maintain definition between each branch or foliage pad. The branches at the tops of the trees tend to be shorter so that lower branches should have more foliage than the top of the tree. The resulting branches could be reminiscent of steps toward the top of the tree. The shorter branches have a functional purpose in addition to the aesthetic appearance. Shorter branches at the tops of trees allow more sunlight to get to lower branches. In pine trees, when lower branches do not get enough sunlight they die. Again evergreen trees and shrubs grown as bonsai can be pruned similarly but are grown on a different scale.

Japanese garden trees are grown on a human scale. The trees tend to be shorter but not so small as to compare to bonsai.

Friday, July 16, 2010

Keeping cool in the greenhouse

In hot weather like this the horticulture staff is trying to stay cool. Greenhouse crops can also suffer from heat stress. The greenhouse is equipped with a pad and fan cooling system to mitigate the heat in the greenhouse. Pad and fan cooling is an evaporative cooling process. Fans on one end of the greenhouse pull the greenhouse air outside while on the opposite end of the greenhouse, water pours through the pads. Air coming into the greenhouse through these wet pads evaporates the water in the pads and cools the greenhouse. Other circulating fans and vents in the top of the greenhouse called ridge vents are also used to cool the greenhouse.

In this hot weather the greenhouse staff will try to stay cool by caring for ourselves, as well as the plants.

Friday, July 9, 2010

Skipper Garden

The Skipper Garden was created by horticulture staff in 2005. It is an AZA Zoo Conservation Project that was created to raise awareness of endangered and threatened butterfly species. The Dakota Skipper was once widely distributed across Midwestern United States. It has experienced significant declines in the last 150 years.

The Skipper's primary reason for decline is the conversion of native prairie to cropland as well as urban development. The Dakota Skipper depends on high quality prairie habitat for survival, and is an important indicator of prairie health. The last remaining stronghold of the Dakota Skipper is in western Minnesota, northeast South Dakota, and most of North Dakota. We have not specifically seen any Dakota skippers in our garden. Minnesota does have more then two dozen other skipper varieties that are native.

Specific plants attract certain kinds of butterflies and moth species. Adult butterflies choose their favorite nectar plants to feed at, and along with the caterpillars that also eat their favorites. Shelter is important to butterflies too. They like a sunny location and away from prevailing winds. Color is a factor to attract them to the garden also. An example, Monarchs use milkweed as a caterpillar food as well as a nectar source when they are adults, they also lay their eggs on underside of the milkweed leaf. Swallowtail larva feed on parsley and lay their eggs on carrots, parsley and dill.

Thursday, July 1, 2010

A little bit of winter in the summer

Over the past week, the Marjorie McNeely Conservatory has received its annual shipments of poinsettia plugs and chrysanthemum cuttings for our Fall and Holiday shows. The horticulture staff have planted the chrysanthemum cuttings and will soon plant the poinsettias. We will be patiently awaiting their successful growth into the mature plants they will become this fall and winter. Suprised that we start them so early? These rooted and unrooted plants come in at a miniscule two to four inches tall!