Herself’s Houston Garden

Could a “hot” flower attract pollinators by serving as a reward in a plant-pollinator mutualism? Many flowering plants produce nectar and pollen as rewards in exchange for pollination services by insects and other animals. Interestingly, however, a few plants have flowers that also produce heat metabolically — so what is the adaptive function of this flower heating?

Susanne Renner from the University of Munich, Germany and Shi-Xiao Luo from the South China Botanical Garden, along with collaborators from China and Taiwan, were interested in determining whether there was a connection between the heating of flowers and the pollination services of flies in an ancient Chinese family, Schisandraceae. Although this family is quite widespread, including Asia and the Americas, its center of diversity is in China, which is one reason Renner and colleagues chose to examine this question in two Chinese Illicium species. Their novel findings are published in the July issue of the American Journal of Botany.

“A few flowers, usually ones pollinated by beetles or flies, produce heat to help scent emission or to create especially attractive egg laying sites for their pollinators,” Renner commented. “Usually such heating occurs only during flowering, simultaneous with the release of pollen and stigma receptivity. We discovered that in an Asian Illicium species, flowers reach their highest temperatures during early fruit development, and experiments revealed that this is for the exclusive benefit of the pollinator’s larvae, which develop in the spent flowers.” Read more, When flowers turn up the heat

Read the paper:
Flower heating following anthesis and the evolution of gall midge pollination in Schisandraceae

It would seem trees are not as dumb as they first appear. When wasps try to lay eggs from outside the flower with out pollinating the flower, instead of inside the flower while spreading pollen the trees drop the fruit containing the baby wasps to death.

While trees often drop unpollinated flowers, they will often hold onto the galls containing the wasps and provide themselves with a future generation of pollinators.

Figs and fig wasps have evolved to help each other out: Fig wasps lay their eggs inside the fruit where the wasp larvae can safely develop, and in return, the wasps pollinate the figs.

But what happens when a wasp lays its eggs but fails to pollinate the fig?

The trees get even by dropping those figs to the ground, killing the baby wasps inside, reports a Cornell University and Smithsonian Tropical Research Institute study published in the Proceedings of the Royal Society B (published online Jan. 13). ( read more read more about tree retaliation )

More information
Abstract
Download the paper (pdf)

Today I went to a talk given by the owner of Pineywoods Nursery on fruit and nut trees and attracting wildlife. Perfect timing as January is when most of the local fruit and nut tree sales take place and after the great freeze of twenty-ten you’ve probably got a few bare spots to fill in the garden.

While Tree Search Farms is a wholesale only tree seller, I’m told the website is an excellent source of information about local fruit trees. Anything they sell does well here.

Useful things I learned at this talk:
If your fruit tree isn’t fruiting it is usually because winter wasn’t cold enough or you don’t have enough pollinators. To attract bees plant various cupheas (Bat faced cuphea, Cuphea ignea, Mexican Heather ) around your fruit trees.

Fruit trees should be heavily pruned, but are easily infected, use sterile tools.

Tips for proper tree planting in Houston

PineyWoods recommends these fruit trees for the Houston area:
PawPaw – fruit is similar to bananas, spoils rapidly, fruit is high theft item from local critters, you’ll need to be quick

Mexican Plum ( prunus Mexicana ) great for dry areas

Chinkapin (Castanea pumila ) Chestnut tree, grows slowly but very tall

Mayhaw (Crataegus opaca) Hawthorne, loves damp areas

Darrows Blueberry ( Baccinium darrowii) stays compact, good foundation plant, need male and female plants to get berries.

Black Cherry ( Prunus serotina) Tall tree, interesting bark

Grapes ( Ison muscadine ) build a very strong trellis first

Mexican Thornless lime- only hybridized limes grow in Houston, this plant is good for pots

Improved Meyers Lemon – best lemon for Houston area

Republic of Texas Orange – only good orange for the Houston area

Rio Red Grapefruit

Blood Oranges

Celeste fig, brown turkey is best

Beauty Plums – need multiple varieties to produce

Red Barron Peaches

Dorsett Golden Apples

Housi Pear

Fuyu persimmons – a great wildlife attractor if you don’t like persimmons

Garnet Pomegranate

Jan 16th
9 am – 2pm Sale/ 730-2pm Symposium
Fruit and Nut Sale ( pdf flyer ) 3033 Bear Creek Drive, Houston.

Jan 23
Program 8-9, Sale 9-1pm
Fruit and Nut Tree Sale Montgomery County Master Gardeners

And if you miss the sales, just drop by Pineywoods Nursery they have plenty of fruit trees for sale.

* Note: When your fruit tree comes back from the great freeze, be sure it’s your fruit tree and not a Flying Dragon which is the root stock most of our fruit trees are grafted to. Flying Dragon is curvy with large thorns, remove immediately or you’ll be sorry.