Sunday, December 21, 2014

The science of leaf colors



Comments by Jennifer of Three Dogs in a Garden and Alison of Bonney Lassie prompted me to look into the science behind fall color.

Carotenoids are present in leaves all during the growing season, their presence masked by the green of chlorophyll, a pigment which allows plant tree to convert water, carbon dioxide, and sunlight into sugar. Carotenoids are responsible for the yellow and orange colors in leaves.


Looking across the neighbor's fields to the maples and oaks beyond on Nov. 26th



Foliage of Rosa rugosa rubra on Dec. 4th. They still have their leaves today.





Anthocyanins, which are produced in late summer and fall, produce red and purple leaf
colors. They also produce the color of fruits such as apples, strawberries and grapes.

Black Highbush Blueberry (Vaccinium fuscatum) on Dec. 5th




Oakleaf hydrangea 'Pee Wee' on Dec. 1st.




Oakleaf hydrangea 'Dayspring' on Dec. 4th. The hydrangeas also still have their leaves.



Sweetgum in my neighbor's front yard, Nov. 6th.


According to the USDA,

"A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions-lots of sugar and lots of light-spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year."

With the exception of a few cold rainy spells and freezing nights, we have had textbook weather for red fall color.

"The amount of moisture in the soil also affects autumn colors. Like the weather, soil moisture varies greatly from year to year. The countless combinations of these two highly variable factors assure that no two autumns can be exactly alike. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors."


Blue plumbago, Nov. 17th


In a dry year all colors here are muted, especially in red maples, one of our principal trees for fall color here. The best year we've ever had for fall color was after Hurricane Floyd. There can be unfavorable changes to the recipe for perfect fall color that can still result in a spectacular year. The summer before Floyd was extremely dry, then Hurricane Dennis hit NC on August 30th, followed by Floyd on Sept. 16th. We received 4 inches from Dennis and 8-10 inches (or more) of rain from Floyd. Then Irene dropped another 4 or 5 inches of rain as she skimmed the NC coast on Oct 17th. Overall, including the rain systems between hurricanes, we received about half of our usual annual rainfall of 47 inches during September and October. I remember the weather as being generally fine after Irene. As if to make a half-hearted attempt to make up for being such a bitch, Mother Nature gave us a magnificent autumn, even better than this year's. Virginia Creeper, which usually just throws out a few red leaves here and there, formed scarlet ribbons that wound around the trees and snaked along the ground. Even the willow oaks, normally not an impressive tree in the fall, turned beautiful shades of gold.


Virginia sweetspire on Dec. 1st



Virginia rose today.


Rainfall has been plentiful the past 2 years. That, along with beautiful bright days and cool nights, created the recipe for the bonanza of fall color here this year.


Black Highbush Blueberries


Wednesday, December 17, 2014

A Very Good Year


As many people have noted, this fall was a beautiful one. And a very good year for the color red.

Naturally most of the leaves are on the ground now but I am still marvelling over this year's color.

*Unless otherwise noted the pictures are from early and mid November.*

The only good quality I can find in poison ivy is its fall color. October 28th



I know that red maples that turn red in fall aren't that uncommon: after all they abound in parking lots, they are featured on blogs and I've even seen the odd wild mature maple whose pure red perfection put the cultivars to shame (here anyway -- Laurrie's red maples in Connecticut are gorgeous), which is why I haven't just bought a cultivar.

But they don't abound on this farm. The only pure scarlet or crimson maples I have seen here are saplings, and it appeared they either outgrew this trait or were eventually outcompeted. (After all, I saw a half a dozen tiny willow oak sprigs yesterday that were red, but the only color I've ever seen willow oaks turn is brown, or, in a very wet year, gold.)

In the small pond that is my farm a red maple that turns red in fall had sort of become my white whale.

This year I saw not one but many.

This maple shone like a beacon in the woods.


Red maple at the edge of one of the floodway fields


There are a few small beautiful red maples underneath the tulip poplars above the house, bright spots among the tangle of Chinese privet and greenbriar that dominate half of the understory. This fall I have been making inroads into the privet and will burn the branches that have fruit. I also plan to take cuttings of the most colorful red maples next year, grow them up, and plant them in here. Already the tulip poplars are dying off and will need successors.



I don't recall this red maple turning such a brilliant shade of any color before, much less red.


The blueberry that started my obsession with the genus Vaccinium is half hidden in the woods behind the electric tape paddock. Even though the trees around it have grown considerably since we first saw it, it still manages to color well. Most of my young blueberries were started from cuttings from this one. Nine to 12 inch cuttings taken in March, even before the limbs have budded out, have worked best.


Most musclewoods turn a vivid yellow or orange or a combination of both, but there is the occasional red. Not a fire engine red mind you, but, well, almost pink.


The tree above wasn't the only one with pink tones. Some of the yellow ones did too.


In fact, I have never noticed so much pink in the fall colors as I have this year.


The sweetgums, usually a combo of red, yellow. orange and purple, had a pinkish glow this year.


Pink sourwood along a path in the woods


Virginia sweetspire typically turn many colors -- yellow, orange, red and purple -- but this combination of purple and pink is unusual.


The blueberry below looked almost florescent pink/red when the light was just right. It colored early for a blueberry and at its peak was spectacular even though it's small still. I marked it with pink tape so I can propagate from it next year. This fall rekindled my interest in plants with fall color and I've been tagging all sorts of things to propagate from next year, including the Va. sweetspire above.

Nov. 3rd


Nov. 12th


Water tupelos turn bright red, but I don't always see the ones in the slough by
the creek. This year I made a point to go down there to see the crimson tupelos.


There are young water tupelos up here too, in the ditches: one behind the big bed pictured
in the last post, and a small tupelo in the ditch beside the drive, near the house.

American beautyberry, winged sumac and water tupelo.

Water tupelo behind the big bed and Southern black blueberry. The blueberry was moved from the
old backyard about 9 years ago, when it was about 6 inches high. It's been very happy in its new spot.

Apricot red maple with the same blueberry and Miss Bessie on
Nov. 10th. This blueberry's fall leaves had amazing staying power.



On Dec. 1st, still fire engine red.


Sorrel trees and blueberries beside drive. Most of the blueberries here are black
highbush blueberries, but there is a Southern highbush blueberry beside the drive too.


A blueberry in the floodway field with the pond.


The brilliant blueberry near the dogwood isn't the only blueberry around. There are several beneath the poplars trees and at the edge of the woods. The small tree to the right is a young swamp chestnut oak, which starts out bright red but usually turns brown at the first freeze. Still, the leaves retains a certain richness of color and when the sun filters through them they still appear dark red.


In a previous post I lamented not having the perfect sorrel tree. I still don't, but I found something close at the edge of the woods next to the old house site.

See the red sorrel tree back behind the yellow pepperbush and the burgundy blueberry? It doesn't appear to get enough sun to bloom, but it turned a almost perfect bright red. Before this year I didn't even know there was a sorrel tree back there.




The dogwood has never looked so beautiful. I hope the young ones end up as nice as this one.
The trees with pink tape are seedlings that I planted. I mark them to make sure I won't cut
them down while trimming around them. There are dogwoods, redbuds, and a sorrel tree here.


When I walked down to the creek to look for possamhaw berries for the Christmas wreath, I was disappointed to see no berries at all. The trees are too shaded now, and there's too much competition from (that damned) Chinese privet. Then, bam! I saw this possamhaw loaded with fruit right by the pond.



The encore azaleas often turn a deep plummy color when the weather turns cold, but this year they turned red.


I've managed to get one small stand of meadow beauty (Rhexia virginica) going in front of the big bed. It was as beautiful in November as it was during the summer. I moved several divisions of meadow beauty into the garden and collected seed to start more. Pale meadow beauty (Rhexia mariana, also known as Maryland meadow beauty) grows here too. Pale meadow has flowers that vary from medium pink to almost white, with thinner stems and leaves than R. virginica. I noticed individuals of both species that were very colorful this fall.

This year wasn't just a good year for fall color, but for the garden as well. Last year I didn't like the garden until September, when all of the Bidens bloomed. This year I liked it much more. Two good years of rainfall have helped. Even more importantly, a change in medication has gotten the fibro under better control. I still have to count out my tasks for the day, dread cold fronts and some days really struggle to get/keep going, but the situation is improved over what it was.


Tuesday, December 2, 2014

A Beautiful Fall


This fall was one of the finest autumns for color in a long time, and started early. I was surprised to see the trees start turning before Halloween this year. Most of the time the weather has been warm and beautiful, with sunshine ranging from golden to milky, and reminded me of an article about Indian Summer that I love. Many of the leaves fell during the recent polar vortex, but there will be color from blueberries, swamp cyrilla etc well into December.

Most of these pictures were taken in the first and second weeks of November.

I was thrilled with the color of the big dogwood this year. (The rest of the dogwoods I have are much smaller trees I grew from seed; this one was revealed when woods were cleared when the house was moved. Once a spindly tree it has filled out beautifully.) It was ruby/claret/crimson rather than the usual dark burgundy and the leaves had a wonderful stained glass quality that shimmered in the sunlight and against the gold and pumpkin shades of the neighboring red maples. I've noticed that many dogwoods in upland areas here turned very dark in autumn, almost reddish-black some years, and I have wondered if the sandy soil has anything to do with that. I don't remember them being that dark in Durham County (clay) or in Chapel Hill (loam over clay).


Red maples vary from yellow to orange to the occasional pure red and every shade in between.




Red maples and willowleaf aster 'Miss Bessie'


This willowleaf spicebush makes such a pumpkin orange splash that I want to grow more
from seed next year and plant them next to the wood's edge, along with the native species.


View from drive above the house and neighbor's pasture. From left to right:
rugosa, first breath of spring (winter honeysuckle), willowleaf aster 'Miss Bessie',
'Knockout' rose, and prairie rose (Rosa setigera). The yellow tree in the
background is I believe a red maple that always turns yellow or gold in the fall.


View of same yellow maple from the front porch.


'Miss Bessie' and American beautyberry. The red tree is water tupelo (Nyssa aquatica).



After sporting many colors, yellow, orange and red, the tupelo turned a brilliant shade of red.
The pictures above were taken November 10th, and the picture below Veteran's Day, November 11th.

This apricot-colored red maple would always catch my eye from inside the house.

The sorrel trees (Oxydendrum arboreum) didn't lose all of their
leaves from leaf spot, so the what was left turned crimson.

The small tree with the fiery color in the bottom left is a witch hazel grown from seed.


The witch hazel never disappoints. The pollen parent was Hamamelis x intermedia 'Jelena', a cultivar that has orange flowers. This tree has yellow flowers (which I like very much). The leaves never drop until after the tree flowers in late winter but that is typical of witch hazels. So is beautiful fall color. Next year I'm going to check to see if this tree produces any seed and is so I will grow more. I want to add the native vernal and common witch hazels too, both of which have yellow/gold fall color and fragrant flowers. The JC Raulston Arboretum used to have Hamamelis vernalis 'Christmas Cheer' and the fragrance was very sweet.


Coastal pepperbush, aster 'Miss Bessie', and the apricot red maple.

Red maples and coastal pepperbush


Coastal pepperbush grows wild all around the old house site.



Coastal pepperbush also grows in the ditch behind the big bed.


The color of the leaves varies from pale butter yellow in deep shade to brilliant gold in the sun.



Japanese beautyberries in the backyard. This year I have gone back and forth wondering if I should let them stay, mostly because next to the house is valuable gardening real estate. The tall yellow shrub in the back is a mockorange, and the purple on the steps is the lining of my winter coat. The stuff in the lower right hand corner is Monarda, Verbena bonariensis, and Baptisia stems, which I will leave up over the winter as cover for the birds.


Rugosas beside the drive. They are just beginning to turn now and often turn beautiful colors in the fall.


Prairie rose (Rosa setigera) in the foreground and water tupelo in the background.
The prairie roses will provide a smattering of colorful leaves until very late.


Speaking of late, some of the Virginia sweetspire and many of the blueberries are at their peak, and the swamp cyrillas and oakleaf hydrangeas are turned about halfway.


Blueberry beside drive, Nov 11th.



 
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