Thursday, January 29, 2009

Winter's Wear

Evergreens are a mainstay of the garden in winter and Kansas City's manic-depressive climate can really create some wear on such plants. Evergreens can be divided into two categories: broadleaved like magnolia and holly and needle-leaf, which includes the conifers. The following is an overview how some of Powell Gardens' evergreens have weathered the winter so far. It has been a wild ride with temperatures around zero but back into the 60s on a bi-weekly basis; and all this with little or no snow cover. (Snow is the best winter mulch against cold!). The coldest temperature has been -4F one morning.

Southern Magnolia (Magnolia grandiflora) grows at its northern limit in the Kansas City area and its leaves are often burned or even killed by hard winters. This is our small, but established 'Kansas City' Southern Magnolia, which is a rooted cutting off the champion Southern Magnolia tree in Kansas City. The parent tree has withstood the test of time and severe winters long into the past as it was brought here by an African American from Mississippi more than 80 years ago. The parent tree is over 40 feet tall and wide with a 18" diameter trunk. Our young plant has held up well with just slight bronzing to the branch tip leaves. You can see we have allowed the plant to have foliage to the ground which helps protect the trunk in winter.

Here are winter damaged leaves of our 'Twenty-four Below' Southern Magnolia. This cultivar of Southern Magnolia is considered one of the hardiest, surviving -24F without injury. Ours has burned on the sunny side from much less cold because it is exposed on the south side of a warm wall. It gets too warm during the day then quickly drops when the sun goes down -- this shocking change of temperature causes the damage, not the ultimate low temperature. By spring, you will be amazed how quickly this winter damage will recover. If this has happened to your own tree, not to worry.

Southern Magnolias sheltered against the north walls of the Visitor Center show much less winter burn because they do not warm up so much during the day. The left evergreen is actually an American Holly but the pyramidal central tree is our selected 'Margarite' Southern Magnolia and the big magnolia on the right / background is the the hardy cultivar 'Edith Bogue.'

This broadleaved evergreen is the poorly known and poorly named Devilwood (Osmanthus americana), which is native to the Southeastern United States. It can become a small tree with very glossy evergreen leaves. This plant is quite hardy once established and as you can see has no damage to its winter leaves.

Nandina or Heavenly Bamboo is a Japanese broadleaved evergreen that is marginally hardy in our area. As you can see this Compact cultivar's foliage has been killed by the -4F cold. Again, we don't let this bother us because it will quickly releaf in spring as the stem has not been injured -- the winter killed leaves are the color of winter grasses. Our Nandinas have killed back to the ground in colder winters but have resprouted each spring.

Leatherleaf Grape-Holly (Mahonia japonica) has leaves that have withstood the cold but I can't quite tell how the "spider" of flower buds atop the leaves have fared. This is one of the first shrubs to bloom, often in February. The flower buds start to emerge in fall and are hardy to around zero or only slightly below. They are very fragrant and yellow when in bloom; last year our shrubs did bloom in March and were awesome. This is a good indicator of moderating winter lows in our area as this shrub never was hardy here until recent years.

Some normally very hardy shrubs like this 'Green Velvet' Boxwood (Buxus hybrid) show some tip damage to leaves. This is because it was trimmed too late in the season and new twigs emerged and didn't harden off well before winter's cold. The burned leaves can easily be trimmed off and the shrub will quickly recover in spring.

Needle leaved evergreens like the Juniper (low and spreading) and the Oriental Arborvitae (Platycladus orientalis) are better adapted to the ups and downs of our winter climate. Oriental Arborvitae is a good choice for our climate, actually better than the American Arborvitae (native to the Great Lakes region) because it handles our hot and often dry summers much better. (There actually is a 'DD Blanchard' Southern Magnolia in the left background of this shot, too.)

This is the lush green foliage of the Hiba Arborvitae or Elkhorn Cedar (Thujopsis dolabrata var. hondai). This shrub is very marginal in our area because it is from Northern Japan in a cooler, more benevolent climate. It is sited off the northeast corner of the Visitor Center where it remains cooler in summer and is protected from winter winds by other evergreens. If you like a particular marginally hardy plant, be sure to know its needs and plant it in a microclimate that suits it.

Here are Golden Threadleaf Sawara False Cypress (Chamaecyparis pisifera 'Filifera Aurea Nana') -- quite a mouthful but a very adaptable, diverse and beautiful evergreen from Japan. We have never had winter burn on any cultivar of this species.

This is a cultivar to the sister species to the above, the Hinoki False Cypress (Chamaecyparis obtusa 'Nana Gracilis'). Hinoki Falsecypress has some of the most beautiful and luxuriant sprays of evergreen foliage but is very marginal in our area. I am pleased most of ours are doing well sheltered on the east side of the Visitor Center.

Off the north end of the Visitor Center this 'Glauca Nana Aurea' cultivar of the Hinoki False Cypress has burned needles. It will recover in spring and probably survive the winter better as it becomes more established and as neighboring evergreens grow and help shelter it. Always try to give your plants an extra chance!

Here you can see the 'Glauca Nana Aurea' Hinoki Falsecypress in full (the golden muffin of a shrub lower left!). It has a 'Blue Pagoda' Blue Spruce (Picea pungens) and a groundcover of sedums dwarfing it. It still makes a nice golden contrast with the blue spruces. We bought these interesting blue spruces as 'Blue Pagoda' but that is not a cultivar name accepted by the American Conifer Society. We don't actually know what they really are even though we are often asked by visitors where they can get one! A lovely dwarf blue spruce at any rate.

This is the lovely dwarf 'Elizabeth' Serbian Spruce (Picea omorika). We like the two-toned blue and green needles. Serbian Spruce is a great choice of spruce for our climate.

The beautiful bicolored needles of this Golden Korean Fir (Abies koreana 'Aurea') almost feel like AstroTurf. This is a much loved ornamental conifer but very touchy in our climate. I am so happy ours is doing great in a cool, raised bed with a Acrocona Spruce sheltering it from summer heat and winter wind.

Our Lacebark Pines (Pinus bungeana) are unfazed by the winter weather and are another choice evergreen for our climate as they come from Northern China with similar winter weather. They do not have the typical pyramidal form that most people demand from a pine but this plant will inspire many future generations on their visit to Powell Gardens as over time they will get the most beautiful bark of any pine. Bark of mature branches will flake off in a patchwork of silver, gray, olive and white -- a reason this tree is often grown near Chinese Temples. Lacebark Pine is a much deserving Plant of Merit that everyone should consider planting for future generations to enjoy. It also has large edible pine nuts so is included our future Heartland Harvest Garden.

Come out and take a stroll around the grounds and enjoy the wide array of evergreens planted throughout Powell Gardens. You will have a great outdoor experience of exercise and fresh air to go along with ideas for your winter landscape.

Friday, January 23, 2009

Harvest Garden Skyline & Instant Apple Trees

Construction continues on our Heartland Harvest Garden, soon to be largest edible landscape in the United States. Below is a scan across its "skyline" from west to east; as taken from the long allee of bur oaks in front of the Visitor Center (January 23, 2009).

The exterior of the barn is nearly complete, the silo is still awaiting its wonderful interior spiral staircase and observatory dome -- the elevator (in the tall shaft) has actually been installed!

Scanning right (east), the arbors of the Missouri Star Orchard are complete at the garden's core: a soon to be backyard fruit production idea garden! Twenty varieties of hardy kiwis and espaliered apples, pears, peaches and cherry trees will shade these beautiful structures. The Missouri Star orchard will also have backyard fruit from groundcovers of strawberries and containers of citrus to blueberry bushes and trained rows of blackberries and raspberries; it should appeal to all tastes.

Scanning far to the east you see the "bones" of the new greenhouse which should be finished shortly. This greenhouse will be a portal to the garden where you can see germinating seeds and the tropical plants that provide food on your plate nearly everyday (bananas, oranges, coffee, tea, chocolate and vanilla!).

The "front yard" of the barn is getting some instant landscaping today--apple trees donated from the old Stephenson's Apple Orchard. Note the huge 90" tree spade from Colonial Nursery delivering the second of 11 apple trees to this space.

The second apple is set soundly in its new home; the first tree on the left was the first Stephenson's apple (Red Delicious), the second tree is a Golden Delicious apple.

Horticulturist Matt Bunch makes sure the tree is set properly in place. We are pleased to have these more mature trees in the landscape and are thankful for them to be donated by Stephenson's Orchard so a bit of our local orchard history may be preserved at the new garden.

Powell Staff led by Gardener Barbara Fetchenhier grew eighty varieties of apples in our nursery for display in the new Heartland Harvest Garden. This variety shall show the dazzling diversity of this most American of fruits (as American as apple pie!). From Lodi apples maturing in early summer and perfect for baking to Granny Smith apples ripening at the end of the season in late fall and perfect for storing for months, there will be an apple for every use and taste ripening through that whole season. Be sure and come out for a taste next season, opening day is scheduled for June 14, 2009.

Tuesday, January 20, 2009

Winter Blooms in the Greenhouses

With the winter blahs upon us I thought I would share some images from the Powell Gardens' greenhouses. Though the greenhouses are closed to the public, these flowers will be on display in the conservatory for the fragrance display or on the grounds after March 15 (if Mother Nature agrees).

Danova Mix Primroses: the flowers are very nicely scented, especially the warmer colored flowers. These are a hybrid polyantha primrose that is occasionally a perennial in a protected, damp spot in the garden. I have had success with them in rain gardens sheltered on the east side of my house. As perennials they bloom in early spring.

Jester Mix Cineraria: also grown for the fragrance display in the conservatory. Cinerarias must have cool weather to prosper so are a great flower for a cool window or in spring containers outdoors. These are currently the Friends Membership bonus plants available at the Front Desk! If you come out and join or bring in your membership plant voucher you can pick one out to take home.

Cyclamen are also a very popular blooming plant for the cool season. They are the main color to the fragrance display.

Here is a first for our greenhouses: a blooming mango tree! Our grafted, dwarf mangoes are currently in flower and we hope that they will produce a few fruit. These plants will go outdoors into the new Heartland Harvest Garden for the summer and we will evaluate whether our hot summers will be long enough to ripen the fruit. Stay tuned....

A closeup of the mango flowers clearly shows their relation to our native sumacs! The flowers have the same richly pleasant scent and look nearly identical. Mangoes and sumac (and cashews and poison ivy) are in the Cashew Family Anacardiaceae. Some people have known allergies to this family. I find mangoes delicious and look forward to a successful ripening process on the fruit of our dwarf "condo" mango varieties.

Our 30 varieties of citrus are also in bloom: some are on display in the conservatory but others like this Citron will be moved into the Heartland Harvest Garden this summer. There is nothing like the sweet scent of citrus bloom! Most citrus fruit take nearly a year to ripen (some mandarins shorter, others longer!).

Our new banana "pups" are starting to grow and respond to the lengthening days. This is the Indian banana 'Raja Puri'. I don't think it will flower until next season (2010). In a couple years we hope to share home grown bananas that were overwintered in our greenhouses and put outdoors for the summer in the Heartland Harvest Garden.

Thursday, January 8, 2009

An Olfactory Experience

Voodoo Lily, Corpse Plant, Leopard Palm, Snake Palm, Konjac or Devil's Tongue! A plant with that many names is lucky to have a single botanical name: Amorphophallus konjac. I will call it the inoffensive name Konjac as per the the definitive book Aroids - Plants of the Arum Family by Deni Brown. This plant has been cultivated in China for more than 2,000 years!

Eric Perrette (Senior Gardener - Grower) at Powell Gardens' greenhouses poses next to our first one to bloom this year. Eric is 6'-1" so our flower is 5 feet tall! At this point he said he is "used to" to the unpleasant smell of the flower.

I asked Eric to give the flower a sniff and you can see the expression! The flowers smell (and look like) rotting flesh so they attract appropriate flies to pollinate them. This is the largest one we've grown; they grow larger over time until the bulb weighs about 22 pounds. The flower emerges from the dormant bulb in winter or early spring.

The foliage of Konjac is quite beautiful comprising the large plant in this container (taken summer 2008). You can see why another name for this plant is leopard or snake palm because of the beautifully mottled black on pink stems. The leaves emerge in spring and are a huge candelabra of foliage through the summer. The plants get larger and larger each year. They are marginally hardy, able to survive outdoors if planted in a sheltered spot near a warm foundation. We let our plants go dormant and store them in the greenhouse headhouse until the flowers begin to emerge -- then we pot them up and move them into the greenhouses. This year they will be on display in the fragrance display! (Come see this plant on display this weekend.) The real nasty smell only lasts a couple days.

We also have two related species: the Elephant Yam Amorphophallus paeoniifolius, which produces an even larger bell-shaped, fluted flower. Its bulb can weigh up to 55 pounds and ours is not old enough to bloom yet. The largest flower of them all is Ammorphophallus titanum the Titan Arum, which always attracts national media attention when it periodically blooms at botanical gardens across the country. Our plant has years to go until it will flower and we will surely let you know when it does!