Thursday, August 4, 2011

The Good, The Bad and The Ugly

THE GOOD: Hummingbird Moth
Hummingbird Moths are smaller even than tiny hummingbirds. A joy to watch, they have similar mobility and proboscis as a hummingbird. One buzzed past me in the garden. It's larger than a Carpenter Bee, but smaller than a Hummingbird. Sphinx moths (Sphingidae and aka hawkmoth or hummingbird moth). Like Hummingbirds, their long proboscises are key pollinators of deep-throated flowers. They can also hover, and hum like hummingbirds. Strangely, their fanned tail strongly resembles a lobster tail.
THE BAD: Hornworm or Braconid Wasp?   
The black spots are "frass".
A few weeks ago we found caterpillar or butterfly eggs on our tomato plants. We looked around and discovered some branches were stripped of their leaves. The kids and I Googled "brown eggs on tomato leaves". Surprisingly, we learned that we had discovered caterpillar scat, called “frass”.

A few clicks later, we had a visual of the suspect who had stripped the leaves on the branches above the scat.

Mostly docile, they become agressive when provoked.
The hornworm on the right doesn't want to share this leaf.

We clipped the branch they were on (often half eaten) and filled a giant jar with tomato branches (mostly suckers).  
The next morning, we fully understood why Hornworms evoke shudders from most gardeners – their  insatiable appetite for our beloved tomato plants.
Several Hornworms tucked in
with a midnight snack.

...and the next morning!

You may be thinking like we did, “Get those things off my tomato plants.” Until I learned that hornworms grow up to be Hummingbird Moths!
Okay, they are really bad if you LOVE your tomato plants, and don't want to share. They have voracious appetites. During my research, I came across a brilliant suggestion to create a Hornworm Haven, ideally located next to the compost bin. In this spot you will toss inedible tomatoes and all plants in the Solanaceae family that are great hosts for Hornworms: tomatoes, peppers, potatoes, and eggplants and flowers like petunias and Nicotiana. Next year, whenever you find a hornworm, clip the leaf or branch they are attached to (they have a good grip and squish easily) and relocate it to Hornworm Haven, a foster home for hungry Hornworms.

Hornworms are one of the biggest caterpillars I've seen, up to four inches long. By the way, this variety of hornworm is called “tobacco hornworms” (Mancuda sexta). Many New England gardeners call these creatures “tomato hornworms” (Manduca quinquemacula). It is confusing, since we find them on tomato plants, and we don't grow much tobacco in these parts. The physical differences are slight, but only the Tobacco Hornworm lives East of the Mississippi and has diagonal white stripes (versus the tomato hornworms v-shaped white markings on its sides) and its red "horn" (the others' are black or dark green). 

THE UGLY: Braconid Wasp

Braconid Wasp (photo: Wikipedia)

One of the most common parasites in home gardens is a small, parasitic braconid wasp. It lays eggs on the Hornworm, the wasp larvae feed inside the hornworm, eventually killing it. The cocoons containing the wasp pupae looks like grains of white rice. When you find a hornworm in this condition, putting it into warm soapy water to put it out of its misery.

Most of the tobacco worms we observed had been victimized by the parasitic Braconid Wasp. Within a day or two, they developed what looked like a coat of grains of rice. A wasp lays eggs on the hornworm. When the eggs hatch, the larvae will make a meal of the hornworm. Each Braconid Wasp can make a huge impact in the local hornworm population.    
For each Hornworm you spare, a Hummingbird Morth will return next year to pollinate your bee balm, butterfly bush, brugmansia, moonflowers, and other deep-throated blooms.

If you can get past that "yuck" factor, they're actually quite fascinating. Next year, we will try to raise ours inside in a butterfly house inside – away from the braconid wasp. I'll keep you posted.

Research and Photos by Renee C. Brannigan

Hummingbird Moth on our Butterfly Bushes

Wednesday, August 3, 2011

Endless Summer Hydrangea - Hydrangea Macrophylla "Bailmer"

Hydrangea Blues?

Mention traditional Hydrangeas and my mind pictures large blue pom-pom-like flowers (mop heads) dangling from ball-shaped shrubs in South County.

Woodbridge's knowledgeable staff has come up with a list of common Hydrangea questions, most specific to the more common mop head variety. We've gathered a few of the most commonly asked questions.
Question: "I heard there's something I can do to make my Hydrangea flowers bluer."
WB:  The acidity of your soil determines the color of your Hyrdangeas (Increase acidicy with sulphur, or if you have a steady supply of pine needles, mulch your Hydrangeas with acidic pine needles. As the pine needles gradually breakdown, they slowly increase the acidity of your soil. .... But, not every Hydrangea can turn blue. White or creamy Hydrangeas, like Oakleaf and Annabelle, cannot turn blue. Most mophead and lacecap Hydrangeas that are pink, blue or purple, can usually change color according to the pH of your soil. You will need to reapply the sulphur throughout the growing season to maintain the bluer blooms. For blooms that are more pink, make your soil sweeter (alkaline) work lime into the soil.

Question: "My Hydrangea plant was a Mothers' Day (or Easter) gift. I've planted it in my garden. It is a nice, healthy plant, but has never bloomed."

WB: Did the pot come covered in foil? If so, it was most likely from a florist/greenhouse that forced your Hydrangea to bloom early. It could be that the type of Hyrdangea wasn't cfhosen for its ability to thrive in our climate. We recommend Endless Summer (blooms continuall all summer), Quickfire and Blushing Bride for their abilitiy to thrive in New England.

Question: "My Hydrangeas haven't bloomed this year. I cut one back in November. The other one was pruned in April."

WB: If they were pruned in fall, winter or spring, the new growth will come from the ground, and not the stems that remain. Hydrangea blooms typically form on old stems. You will have a stronger, healthier plant. I am sorry to say, that you won't have blooms this year.

Question:"This spring, the leaves on my Hydrangea were killed off by a late cold snap. Is that why it hasn't bloomed this year?"

WB: Not only were the leaves damaged by the freezing temperatures, the tiny buds that were forming were damaged, too. Next winter try covering your Hydrangea to keep them cozy until after the danger of a cold snap is past.

I visited Woodbridge Greenhouses again this week. I'm thrilled to have found varieties of Hydrangea that bloom ALL SUMMER LONG -"Endless Summer", in addition to the traditional round mop head, they also have "Twist and Shout", a lace-cap Hydrangea that defies the Hydrangea stereotype.   Enjoy.  I know my family will, all summer long!

Bee Balm

"Knowing trees,

I understand the meaning of patience. 

Knowing grass,

I can appreciate persistence."

- Hal Borland