Chamaecyparis obtusa

Volume 2, Issue 21
June 30, 2011
Chamaecyparis obtusa
Chamaecyparis obtusa, otherwise known as Hinoki Falsecypress,
is native to Japan, where it is an important timber tree and is considered
sacred in the Shinto faith. A large, broad, and conical tree, it can reach 125
ft. in the wild and 50 to 75 ft. in cultivation. The foliage is a rich, dark
green with bluntly rounded leaves (hence obtusa). The bark of this tree
at maturity is a bright red-brown, which peels in long, thin strips. There
are many, many cultivars of this species, many of them challenging to
differentiate from one another. Here at Lockerly, we have records of 31
cultivars of this species that were planted in our conifer collection over
the years, but only 6 of these are known to have survived. ‘Nana Gracilis’
is one of the best in our collection. This cultivar has glossy dark green
foliage and a conical habit, reaching 3 ft. at maturity. It is a universally
admired cultivar that has been cultivated in gardens for over 100 years.
We also have ‘Crippsii’, a slow-growing, wide-spreading cultivar with golden
yellow, ferny foliage. It has great winter color and is a choice accent plant. Our
‘Crippsii’ may very well be the largest specimen of this cultivar in the state.
Our other surviving C. obtusa cultivars are:
Table of Contents
Chamaecyparis
obtusa
pg. 1
Summer Stress
pg. 2
‘Filicoides’: a small open-growing conifer with long, thin branches and
green fern-spray foliage. In time it reaches 5 ft.
‘Aurea’: a broad pyramidal conifer with whorls of rich golden yellow
foliage. Grows up to 15 ft.
‘Juniperoides’: a dense slow-growing dwarf with green foliage that can
reach 10 ft.
‘Tetragona Aurea’: compact upright but variable, moss-like foliage,
golden yellow color when grown in sun, slow-growing, benefits from
trimming.
We’ve planted many more C. obtusa cultivars in the Conifer Reference Garden over the past year, and some
are doing really well. We’ll see which ones withstand the test of time in our challenging climate.
Summer Stress
We have been experiencing a real heatwave in middle Georgia, and these conditions
can make life miserable for both plants and
gardeners. Temperatures in the high 90s and
several weeks without rain can lead to serious,
sometimes fatal, conditions for landscape plants.
Here at Lockerly we have lost a number of
mature trees and shrubs in the past month that
were not under irrigation. The plants that are
among the first to show major heat and drought
stress include dogwood, Japanese maple,
oakleaf hydrangea, fothergilla, and azalea.
Plants like hydrangeas are good indicators of the
stress your landscape is undergoing. If they look
droopy, take this as a sign that all the plants in
your landscape need water!
Heat stress symptoms range from wilting and pale yellow
color to marginal leaf scorching, leaf cupping and defoliation. Trees
and shrubs planted in the past year and those with other stresses (root
damage from soil compaction, for instance) are the most seriously
affected. Drought makes the situation much worse. Drought stress is
often compounded by an increase in insect and disease problems.
Powdery mildew and spider mites are common predators of stressed
plants.
If your landscape plants get too stressed, consider cutting them
back to help conserve water. If they are wilting badly and you are
unable to irrigate them sufficiently, cutting them back will help them
survive. Plants become stressed when their foliage demands more water
than their roots can supply, and reducing a plant's top area will reduce
the demand on its roots.
One of the best ways to reduce plant stress from heat and drought
is to use a generous layer of mulch over the roots. Fine-textured mulches, such as pine straw, pine-bark mininuggets, or composted wood mulch hold moisture in the soil better than coarse-textured mulches. Lastly, don’t
even think about applying fertilizers when plants are undergoing drought stress. Chemically, fertilizers are salts,
and fertilizer salts in dry soil will pull water from the roots, further dehydrating them.
Good luck, and try and stay cool!