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Magnolia Propagation Research

Not all great plants make their way to garden centers for a variety of reasons.  One significant reason that prevents some beautiful specimens from entering the mainstream is difficulty in propagating and producing them in enough numbers. There are many evergreen magnolias from Asia that have proven very difficult to produce in any way other than seed.  Seed production for trees can be impractical in most cases for many nurseries for a variety of reasons.  At the JC Raulston Arboretum, we've been growing one species which we think is quite outstanding - Magnolia yuyuanensis or Chinese wood-lotus.  It bears pure white cupped flowers with deep red stamens in spring followed by pinkish-red seed pods and all backed by narrow, glossy, evergreen foliage.  Our plants have survived temperatures as low as -19C (-3F) for short periods and have had no issues with temperatures in the low teens.CTG18608

The propagator at Atlanta Botanical Garden, Ethan Guthrie, has been using very high rates of rooting hormone (50,000ppm KIBA or potassium salt of indolebutyric acid).  Typical commercial concentrates of KIBA top out at 10,000ppm KIBA so Ethan's rates are through the roof but you can't argue with his success.

An NC State Horticultural Science graduate student, Dominic Gillooly, is now working with Dr. Tom Ranney to get a handle on propagating M. yuyuanensis and other evergreen species.  He'll be trying rooting hormone rates of between 10,000ppm to 50,000ppm with a control of 0ppm on these magnolias to try to develop a commercially feasible propagation regime for these outstanding plants.

Graduate student Dominic Gillooly collecting a couple hundred cuttings of Magnolia yuyuanensis for a research project.

Knowing how difficult producing this plant from cuttings has proven to be we planted a hedge of them years ago with plans to coppice or cut them back regularly to produce good cutting wood for research on the best propagation methods.  We love it when our plans and our faculty and student's needs coincide.  If Dominic and Tom can produce some good results, we'll be sure to get these great magnolias and the knowledge of how to produce them into the hands of NC nurserymen fulfilling J.C.'s exhortation to "Plan - and Plant for a Better World."

Follow me at @jcramark because life is too short for boring plants.

Check out all the happenings, see more images, and learn more at the JC Raulston Arboretum where we are Planting a Better World.

Plant Buggy Sales - September 27, 2013

Fall is for planting!  So come on out and see what we have for sale this week on our Plant Buggy outside the Bobby G. Wilder Visitor Center.  Remember it is cash or check only and we don't have change.  Most plants are $5 with a few $10 ones thrown in as well. Our staff and volunteers continue to propagate some of our favorite plants to offer our visitors.  Here is a selection of a few of the plants on the trailer this week.

Aster ageratoides 'Ezo Murasaki' - An outstanding Japanese selection of Asian aster. It has incredible medium-purple, frost-resistant fall flowers. It forms a low mat of foliage and spreads quickly by underground stolons. Be prepared, because it will fill a large area in the garden in short order.

Simply stunning in fall, makes a great ground cover in sun to part shade.

Callicarpa japonica 'Shiji Murasaki' - A heavily variegated form of beautyberry with green leaves splashed and speckled white. New growth emerges pink and young stems are pink. Unlike the typical Japanese beautyberries, this form seems to grow somewhat upright and is heavily branched with none of the arching characteristics usually seen. Flowers are pinkish and so far we have seen no fruit set. Our plant has been surprisingly vigorous for the amount of variegation and has not burned in full sun with minimal irrigation. Grows best in sun to shade conditions, reaching an ultimate size of about 6'.

Heavily variegated foliage is surprisingly sun tolerant.

Clethra barbinervis - Whether you call it Japanese pepperbush or Japanese summersweet, you will admire it for its sweetly-scented white flowers, produced in summer, and the richly exfoliating bark specimens attain with age.  Grow as an upright, open shrub or a small flowering tree in sun to shade.

Masses of white summer flowers are sweetly fragrant.

Gardenia jasminoides 'Shooting Star' -  ‘Shooting Star’ is a compact cultivar of gardenia noted for its winter hardiness and large, fragrant, single white flowers up to 3” in diameter in late spring. Its glossy, evergreen leaves will add beauty to your garden all year long.

Hydrangea serrata 'Ô amacha Nishiki' - A lovely small lacecap hydrangea with flowers that tend toward the pink rather than blue.  The foliage is heavily dusted with creamy white which helps light up the shade garden.

Pink lacecaps and speckled variegation make this plant a winner.

Magnolia maudiae - Enjoy the intoxicating fragrance of pristine white flowers in late winter on this evergreen magnolia. Flowers are large (4"-6") and it has been described in bloom as "one of the greater surreal experiences of horticulture."  Plant in a location that has protection from cold north winds.

Pristine white winter flowers backed by evergreen foliage are a delight in the garden.


Sinningia 'Bananas Foster' - From May until frost you will enjoy this delightful hardy gloxinia in your garden. True to its name, it produces dozens of 2" pale yellow tubular flowers. It is very drought tolerant and perfect for a rock garden or other sunny location.  It is such a very cool and desirable plant.

Tubular yellow flowers on red stems last all summer long.

Sphaeralcea 'Shell Pink' - This lovely globe mallow is widely touted as an annual plant but has been perfectly hardy for us over the last five years in a well-drained, sunny spot.  The hibiscus relative makes a spreading plant with silvery leaves and pink flowers.  It will look great in containers or hanging baskets as well as in the garden but may not be hardy in a pot.

Pink hibiscus-type flowers are quite lovely.

Other plants on the cart this week include:

XFatshedera lizei 'Curly'Amsonia hubrichtii,  Sedum emarginatum 'Eco-Mt. Omei'Buxus sempervirens 'Vardar Valley'Ruellia simplex 'Chi Chi'Hippeastrum 'Scarlet Baby'Sinningia tubiflora

Follow me at @jcramark because life is too short for boring plants.

The new JCRA Plant Buggy for onsite sales.

Check out all the happenings, see more images, and learn more at the JC Raulston Arboretum where we are Planting a Better World.

Pic of the Day - Magnolia virginiana var. australis 'Green Shadow'

The pure white flowers are deliciously fragrant. Few trees have as good a pedigree as this magnolia.  Plantsman Don Shadow of Shadow Nursery in Tennessee selected this plant from a large batch of seedlings he grew out from the late Dr. J.C. MacDaniel, a prolific plant breeder from the University of Illinois.  Magnolia virginiana var. australis 'Green Shadow' makes a neatly oval outlined tree to about 30' tall by about half as wide.  The clean, green foliage with silvery backs is highlighted by virginal white flowers to 3" across over an extended period from spring well into summer.  The heaviest flowering is early in the season but sporadic flowers appear for up to 4 months.  The sweet, lemon scented flowers are followed by curious bulbous reddish fruit which can actually be quite showy.  This is one of the fastest growing of the southern (var. australis) types of sweetbay magnolia we've grown here at the JC Raulston Arboretum.  This tree is reliably evergreen through USDA hardiness zone 7 but can be grown in much colder climates.  Magnolia virginiana grows naturally in swampy soils and while perfectly happy in drier spots, it also tolerates permanently and seasonally wet locations and makes a great specimen in rain gardens.

Multi-stemmed and low-branched trees can be especially attractive.

Pic of the Day - Magnolia figo var. crassipes 'Purple Queen'

20130530-105808.jpgThis evergreen magnolia (formally included in Michelia) makes a large, multi-stemmed shrub with glossy deep green foliage. This variety of banana shrub blooms over a long period from spring into early summer with dark burgundy flowers. The blooms have a fruity fragrance reminiscent of bananas. Best in full sun to light shade in average well-drained soil.