Thursday, December 27, 2007

More "Evergreens" to see at Powell Gardens


Lacebark Pine (Pinus bungeana)
Lacebark Pine is a very hardy pine from Northern China. It is a "bushier" pine with healthy green needles at all seasons but develops some of the most beautiful bark of any plant with age. Our plants are 10 years old and over 15 feet tall. They are just starting to get exfoliating bark if your peer in between their lower branches. This is definately a pine you want to have as many branches low to the ground as possible because one day those will form the multi-branched show of beautiful bark. (Note we have NOT pruned ours up) Someday these plants will be spectacular trees at the northeast corner of the Visitor Center. I cannot say it enough how important it is to plant trees that future generations will enjoy!


'Santa Rosa' Sweetbay (Magnolia virginiana var. australis)
Powell Gardens has one of the finest collections of magnolias outside the coasts! We have most of the cultivars of sweetbay and this one ('Santa Rosa') is our most evergreen. Santa Rosa is listed as hardy in zone 7 or zone 5 depending on your resource. The cultivar was selected from northern Florida but many plants from there have proven hardy while others not so. So far our plant has weathered -9F so is at least zone 6 hardy. Sweetbays are vulnerable to cold if they are dry and are much hardier if grown where they have wet feet. They make a great rain garden plant. Walk around the Visitor Center and you will see other cultivars -- our Santa Rosa sweetbay can be seen on the north side of the Visitor Center. Come back in late spring (usually late May) to smell its namesake flowers!


'Vintage Gold' Chamaecyparis or Sawara False Cypress (Chamaecyparis pisifera)
Vintage Gold Chamaecyparis has some of the most beautiful golden sprays of foliage you can grow here. It is a difficult to find conifer but we will sell small starts of it at our annual spring plant sale the first weekend in May. This Chamaecyparis is reliably hardy into zone 4 (Minnesota) and is heat tolerant too. Look for our plants on the east, overlook side of the Fountain Garden where they are used in a tapestry planting with other shrubs and perennials. They would become a small tree if unpruned but we will shear ours so that they remain shrubs. Deer love this plant and they end up shearing it for us in winter.


'Hazel Smith' Giant Sequoia (Sequoiadendron giganteum)
Marvin Snyder, past president of the American Conifer Society, gave us a small start of this -- the supposed hardiest cultivar of the giant sequoia. I didn't think it would survive but planted it in the sheltered space east of the Visitor Center. It has thrived and grown 2-3 feet per year! It has beautiful blue-green needles and a strongly pyramidal form. The base of the trunk is already gaining considerable caliper. Come back in 3,000 years and see if it rivals its brethren in the California Sierras. It is considered the largest species of tree on earth.


'Cannaertii' Juniper or Eastern Redcedar (Juniperus virginiana)
The Cannaertii Juniper is a selection of our native Eastern Redcedar from Kansas. It is grown for its striking form and the fact that its needles remain dark green in winter instead of turning reddish like most of its wild siblings. It is a female cultivar and is heavily studded with blue, berry-like cones in fall and winter. It is a premier bird attracting tree as its "berries" are eaten by many species of birds including: Cedar Waxwing (see Linda Williams' photo from these very trees in this blog), Northern Mockingbird, Eastern Bluebird, American Robin, and Yellow-rumped Warbler. Our trees are located between the parking lot and the Visitor Center.


'Foxtail' Blue Spruce (Picea pungens)
Foxtail Blue Spruce is one of the bluest of blue spruces and has begun to grow very fast for us. This tree is south of the Rock & Waterfall trolley stop. Blue Spruce does very well for us and is the state tree of Utah and Colorado. In our humid climate it likes to grow in the open where there is good air circulation: it doesn't like other plants or trees touching it! It can succumb to needle blights and cankers under such situations. We have provided plenty of space for ours to become a large evergreen tree.


'Golden Ghost' Japanese Red Pine (Pinus densiflora)
Golden Ghost has proven itself as the best variegated pine! Others we have tried look fine in the summer but sickly in the winter while 'Golden Ghost' retrains its crisp yellow striped needles through winter. Our small tree was donated to us by Marvin Snyder and can be found north of the Visitor Center in the new and expanding dwarf conifer garden.


'Compacta' Bosnian Pine (Pinus heldreichii)
Bosnian Pine is a rather rare pine that is becoming more available in nurseries because it has proven itself very hardy and disease resistant. While Austrian and Scotch Pines die in droves from disease this pine thrives. We planted our trees between Scotch Pines we knew would succomb to disease (almost all our Scotch pines have died and been removed). Our Bosnian Pines have thrived despite severe droughts and no care in a meadowy area at the end of the Nature Trail (opposite the Rock & Waterfall trolley stop). Our trees are the slower growing, more compact cultivar aptly named 'Compacta.'


'Greenleaf' Holly (Ilex x attenuata)
Greenleaf Holly is commonly sold in local nurseries as Greenleaf American Holly. It is actually a hybrid and not nearly as hardy as a true American Holly (Ilex opaca). (It is a hybrid between American Holly and the Gulf Coastal Dahoon Holly (Ilex cassine). I depicted it to show that it often suffers winter burn and discoloration out here at Powell and has suffured severe dieback in past severe cold while nearby Southern Magnolias and American Hollies are unscathed. It has hybrid vigor and grows very fast, so unlike American holly which takes years to become a nice specimen, this tree can be quickly produced for our instant gratification. It is fully hardy in sheltered, more urban parts of our region and a fine ornamental under such circumstances. It is a female holly and is covered by red berries wherever a male pollinator is growing nearby. Look for our plant on the south side of the Visitor Center.


Cholla (Opuntia imbricata) and Arkansas Yucca (Yucca arkansana - formerly Yucca glauca var. mollis)
Here are some evergreen for hot, dry spots! The cholla is native from Southwestern Kansas to throughout the American Southwest and is very hardy. It provides striking winter interest but is at its best with its magenta flowers in early summer. The Arkansas Yucca is a unique, fine textured yucca from the Ozarks and Ouchita Mountains and is also very hardy. It has tall spires of beautiful greenish-white flowers in early summer. Look for these plants in the Powell Gardens parking lot where our arboretum of all the native woody plants of Kansas and Missouri are planted.

All photos taken by Alan Branhagen at Powell Gardens on December 20, 2007.

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