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Posts Tagged ‘Parthenocarpic seeds’

Autumn is known for its wonderful colors, the yellows, oranges reds and maroons add a bright splash of excitement to the coming winter season. I enjoy the many native trees in the area with their amber shades. One somewhat rare tree which should become much more widely grown is  the Paperbark Maple(Acer griseum) which has bright buttery yellow to crimson coloring. It is one of the best small specimen trees for a typical urban setting.

 

Autumn color of the Paperbark Maple some of the latest in the year for the Maple family.

Autumn color of the Paperbark Maple some of the latest in the year for the Maple family.

The year was 1901 Paperbark Maple was introduced to Europe by way of Vietch’s Nursery.  Acer griseum is another fabulous find by Ernest (Chinese) Henry Wilson. He was on one of his many explorations for plants in China looking for the famous handkerchief tree(Davidia involucrata) which was known but not collected at that time. The area he was exploring was central China.

 

 I can imagine Ernest 'Chinese' Wilson finding Acer griseum in the forest looking like this, bark glowing in the light.

I can imagine Ernest 'Chinese' Wilson finding Acer griseum in the forest looking like this, bark glowing in the light.

 

Paperbark Maples come from central China from north-east Gansu  province traveling west into Hebei and south to Sichuan and south-west into Hunan.  The tree is found at fairly high altitudes of 1500-2000 m. (5000-6500ft.). It is one of the better but not the most famous find of the over 1500 named plants which ‘Chinese ‘ Wilson brought to horticulture during his incredible explorations.

 

The peeling 'paperbark' of Acer griseum is very beautiful throughout the year.

The peeling 'paperbark' of Acer griseum is very beautiful throughout the year.

 

Acer griseum does not have the typical ‘maple’ shaped leaves, instead it is trifoliate. This gives it a delicate feeling as the foliage looks fine in texture. Many people are not familiar with the other leaf forms of  Maples. One similar leaved maple is the Box Elder(Acer negundo) which is extremely hardy and produces masses of seedlings making it become somewhat of a pest in many places.

 

 The delicate looking trifoliate leaves of Acer griseum come to life in flaming fashion in the fall.

The delicate looking trifoliate leaves of Acer griseum come to life in flaming fashion in the fall.

Acer griseum is an excellent small tree for the home and should be seen more often. One issue that has become known is the difficulty germinating the seed which is said to be between 2 and 8%. It produces a good amount of  seed but most of it has proven to be parthenocarpic. Parthenocarpic is seed which developes but is sterile. THere are now plans to make new collections of wild seed to increase the gene pool of this tree and increase the likelihood of better seed viability. Another issue is that these trees are androecious with males and hermaphrodite flower structures.

 

 

Acer griseum produces a great amount of seed but little of it is viable.

Acer griseum produces a great amount of seed but little of it is viable.

 

Acer griseum has many feature which lead it be seen as a specimen tree. It is attractive throughout the year; spring gives us delicate blooms and the flush of new leaves, summer is seen with the delicate green-blue of the leaves, autumn highlight the brilliant color late in the season and winter comes when the bark is highlighted especially with backlighting. The size of the tree is also especially appealing and works well in most garden situations whether they be in a border or by itself.

 

This wintery Acer griseum is found in Finnerty Gardens along a less traveled path where the bark is highlighted.

This wintery Acer griseum is found in Finnerty Gardens along a less traveled path where the bark is highlighted.

Acer griseum grow in full sun to part shade but not deep shade. They like fertile acidic soil which is well-drained. They need average amounts of waster and are not noted to be drought tolerant. They have few pests or disease. They can be pruned but it is rarely done except for  shaping or removal of damaged limbs and this is best done in late autumn or winter. They are slow-growing trees which can grow to 10-20 m (30-60ft). They are fairly hardy and are rated taking -20c(-4f) and higher.  Paperbark Maples are easily transplanted.

 

This Acer griseum is in the back yard of a garden in Vancouver.

This Acer griseum is in the back yard of a garden in Vancouver.

 

Paperbark Maples are propagated by cuttings or by seed and are somewhat rare in nurseries. They are becoming much sought after by good landscapers and gardens are more expensive to buy than many other trees. It is a tree I recommend for the small city gardens as a specimen or accent tree.

Marveling at this Maple:

An excellent technical description of the tree: https://appserver1.kwantlen.ca/apps/plantid/plantid.nsf/lookup/2C6CC1B288E3831088256EB500662648?OpenDocument

Parenthocarpy in seeds: http://en.wikipedia.org/wiki/Parthenocarpy

Ernest Henry Wilson: http://en.wikipedia.org/wiki/Ernest_Henry_Wilson

……I will be looking forward to seeing you again soon here…..

 

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