Tardily Deciduous

Yes, there is a horticultural term for deciduous plants that hold their leaves into winter: tardily deciduous. As the temperatures get colder these plants will gradually lose more and more leaves until they are nearly bare by mid-winter.

No, these Northern Sweetbay (Magnolia virginiana var. virginiana) magnolias in front of the Visitor Center are not sick! They are just now beginning to lose their leaves as the cold weather has arrived. Sweetbay magnolias are generally not recommended for such a windswept site but because the planting beds are so poorly drained (wet!), this was a good choice here: Sweetbays are hardier if they have constant moisture and are native to wetlands. As these small trees mature (15-20 feet) they will create a more comfortable space to sit in front of the Visitor Center. The sweet scent of their late spring and summer blooms is intensely lemon-like.

Here is an evergreen cultivar of the closely related Southern Sweetbay (Magnolia virginiana var. australis) 'Milton'. You can see its leaves are still dark green above and blue-green below. Severe cold (-10F) can damage the leaves and make them drop. Southern Sweetbays are usually more tree-like (20-30 feet here) and less bushy than their northern cousins.


Can you spot the tardily deciduous plant in this image? It's the front and center ball of olive green: Winter Honeysuckle (Lonicera fragrantissima). As the weather gets colder more of its leaves will discolor and drop. The pinkish brown leaves to the left are the marcescent (dead leaves that don't drop) foliage of the White Oak (Quercus alba) while the dark green plant in the background is the truly evergreen Southern Magnolia (Magnolia grandiflora 'Twenty-four Below').


A close look at a twig of the Winter Honeysuckle shows a swelling bud: it is a flower bud that may open as soon as next month if we have a spell of mild weather. Winter Honeysuckle has very strongly lemon scented flowers that perfume a wide area. The flowers can be damaged by severe cold but the shrub always continues to sprout new flowers until mid-spring. This non-native honeysuckle is not an invasive like many of its cousins. It becomes a huge shrub that can be trimmed up like a little multi-stemmed tree.


Looking out the windows from the Visitor Center the evergreen Southern Magnolias defy the winter season with lustrous green leaves. Few broadleaf plants are evergreen in our climate. These are some of the hardiest selections and we wonder how they will fare if we again have our record low temperatures.


Looking north from the Visitor Center you can see how the landscape around the Visitor Center has many plants with winter interest -- evergreens! The pair of potted plants are Bracken's Brown Beauty Southern Magnolias, the center left plant is an American Holly (Ilex opaca) and the center right plant is a Lacebark Pine (Pinus bungeana). Stay tuned for more on evergreen plants in the next blog...

Whimsical Christmas Trees

Anne Wildeboor (Horticulturist - Seasonal Displays and Events) ties on the final "star" to our trio of whimsical Christmas trees installed in the Visitor Center's Grand Hall. The trees are a trio of living 'Van Den Aker' Alaska-Cedars (Chamaecyparis nootkatensis) and will be planted outside in the gardens next spring. They are a perfect example of whimsy: some think they look like Dr. Seuss while others are reminded of Charlie Brown's tree. We contemplated hanging a Grinch or Cat-in-the-Hat hat but the red ornament balls do the trick!


The trio of trees with Anne from another view.


Jennifer Comer (Senior Gardener - Perennial Garden) places the finishing strings of lights on the trees. Volunteers began the process yesterday and said the trees were more difficult to light than they imagined.


Janet Heter (Senior Gardener - Rock & Waterfall Garden) adds some holiday color (white, frilly flowering cyclamen) to a container of Teddy Bear Magnolia in the Grand Hall. The finishing touches of the Christmas display are being completed today but you will have to come out yourself to see the final product. By tomorrow the final poinsettias and the last train will be installed. I think this Grand Hall display along with the fabulous retro aluminum Christmas trees in the conservatory create a most interesting holiday display. Enjoy!

Old Hickory

Hickory Nuts are one of the tastiest of the season's wild bounty. Native Americans crushed and boiled them to extract their nutritious fat and oils for use as cooking oil or to add to other foods.


Here I placed some Shagbark Hickory (Carya ovata) nuts on the planting plan for the Living off the Land portion of the new Heartland Harvest Garden. Hickories are a prime example of a native edible. Shagbark Hickory nuts are delicious but it's not easy to crack and extract the nutmeat. It is worth the effort as hickory nutmeat is great raw or in hickory nut pie and other baked goods!


Horticulturist Richard Heter stands next to one of Powell Gardens' old Shagbark Hickories. This tree is only 3 feet in diameter but 100 feet tall (see the series of images below looking up to the crown of this tree). It grows in the core of Powell Gardens up the creek bed behind the Marjorie Powell Allen Chapel. Powell Gardens has several presettlement hickories--the easiest one to see is in the road ellipse in front of the Visitor Center. The bark of local trees is not as shaggy as typical; I will have to find out why.






Hickories are also valued for their strong, shock-resistant lumber and of course it is a favorite for smoking food: hickory smoked flavor is legendary. Hickories are never seen in nurseries and rarely planted by gardeners. A seedling tree can grow a 5 foot tap root--with little above ground growth. With proper root pruning they can be grown in special containers or root bags for transplanting. This strong root growth contributes to the drought tolerance and longevity of the tree.


See below for a quote from my favorite tree book: Native Trees for North American Landscapes by Guy Sternberg. (A great gift for anyone with interest in trees and available at Powell Gardens' Gift Shop).


This is the great tree whose name was adopted by Andrew "Old Hickory" Jackson, the hickory-tough, battle hardened, seventh president of the United States. He even planted a few shagbarks at the Hermitage, his home near Nashville, TN (they are still there today!). It is unfortunate that few others have followed his example, as hickories are notoriously slow to mature and challenging to transplant, and modern folks want "easy" trees. Many of our most magnificent specimens in wooded neighborhoods are remnants of presettlement vegetation, and as they begin to die out, no one is replacing them. Please plant a hickory -- any hickory -- for posterity! My sentiments exactly.

Shellbark Hickory (Carya laciniosa) has the largest nuts of any but they are still hard to crack. These are often called Kingnut or Missouri Mammoth Hickories. We have several of these trees in our Heartland Harvest Garden nursery. They will be worth the wait and I know future generations will be glad we planted them. They usually grow wild in deep soils on flood terraces in our region.

These are Mockernut Hickory (Carya tomentosa) nuts. These nuts are so hard to crack that they make a mockery of anyone who tries. The tree is a magnificent and beautiful plant, especially in fall when cloaked in golden foliar attire.

Red Hickory (Carya ovalis) has reddish tinted brown nuts. This tree often grows on very dry ridges in our region. Botanists have trouble differentiating it from the Pignut Hickory (Carya glabra) whose nuts were at least good for pig fodder.

The toughest of our local hickories is the Black Hickory (Carya texana). This tree grows really slowly and often is just a small tree growing on some or our poorest, driest soils. The trunks of larger trees are charcoal black.

I couldn't find any nuts of our most well known hickory: PECAN (Carya illinoinensis)! This image is looking up into trees in our nursery. Pecan nut husks remain up in the tree like black "flowers." The nuts have fallen and are immediately devoured by a whole host of creatures from people to 'possoms, Blue Jays and crows. Pecans are native to floodplains in the immediate area and several selections that will thrive in our area and produce larger-sized, easier-to-crack nuts than the typical wild trees can now be purchased from mailorder nurseries. These "northern" pecans have rich flavor, superior to the paper shell "southern" varieties commercially grown outside the pecan's native range, which is from Illinois and Missouri southward into Texas.

Some of our pecans in our old nursery are getting quite large. We do plan to transplant some of them, hiring Colonial Nurseries' largest tree spade. These were twice transplanted in youth so should make the transfer. Seedling and sapling pecans are true to their hickory relatives and grow a long deep taproot that makes them difficult to transplant -- the earlier transplantings helped us prune their roots for future moving. Look for these trees in the future pecan orchard of the Heartland Harvest Garden. They are already bearing nuts.