Friday, August 23, 2013

Mid-summer's Little Blooms

In the middle of summer there are many big blooming native plants like Cone Flowers and Black-eyed Susans.  A next post I will take a look at some of the 'prettier' natives that are in bloom now.  But this post I will show you some of the natives blooming with small pale or white flowers.  Many of these could be considered weeds, but I had not ID'ed many of them before, and, of course as native species they are part of the 'original' ecology of the area.

This Virginia Stickseed is about 2 feet tall.  The horizontal
sprays of seed pods give it a unique texture.
The first plant that literally caught my attention was Virginia Stickseed, Hackelia virginiana.  As I was clearing stilt grass from a planted area several branches from this plant caught hold of my sleeve.  When I pulled back These branches broke off, transferring the sticky burr-like seeds onto my shirt.  Originally about 4 feet tall, parts of this plant fell over due to the weight of seeds.  Rather than noticing the small white flowers, what I see now is a a textural affect from the horizontal branches laden with burrs.
Here you can see the progression from flower to burr.  This bee fly is a pollinator
 for many small flowers.  Its larvae are parasites that feed on other insects.

This plant has a highly branched forms, others
in less disturbed areas grow as a single upright stem.

Nearby was one of my favorite little natives, Indian Tobacco, Lobelia inflata.  It is not really showy.  The blue flowers are not very big and the small flowers are spaced widely on the stalk.  What I think is so cool are the swollen ovaries (hypanthium) that form after the flower fades.  This feature is the reason for the species name, inflata.  This plant is used as an herbal remedy for many ailments, particularly as an emetic, but it is also quite toxic.  I've tried growing these from seed indoors under lights with limited success.  It seems to grow better as a 'weed', than as a cultivated plant.

Here you can see both the pale blue flowers
and the inflated hypanthium.

The coarsely toothed, oppositely arranged leaves
on long petioles are similar to those of nettles.

White VervainVerbena urticifolia, has spikes of tiny white flowers.  The plant has a rough appearance with its large, coarsely toothed leaves.  The species name uricifolia refers to it having nettle-like leaves.  This is not a particularly attractive plant, but its flowers are visited by a variety of bees and its seeds are consumed by birds.

Here's a closer view of the flowers of White Vervain.  It seems like the tips of the flower stalks are the place for small insects to hang out.

The current botanical name for this
Horseweed is Conyza canadensis.

When I looked past the white Vervain I saw what thought was more of the same, but on second glance I realized that I had yet another plants with little white flowers.  I keyed this one out as Horseweed, Erigeron canadensis, which has been updated as Conyza canadensis. On examination its form is very different from the verbena, with narrow leaves occurring alternately along the stem.  The main similarity was that the flower stalks originated from the leaf axils.  Similar to members of the genus Erigeron, its flower is composite type with many small rays.  This annual is commonly seen in waste areas and fence rows.

A green sweat bee visiting a Horseweed flower.

My last plant for this post was discovered with its flower stalk sticking out of some berry vines in a woodland edge habitat.  Normally I leave a plant in place until I know what it is, but this one had me worried.  It had characteristics of Polygonum (Knotweed) and with its white flowers I immediately thought of Japanese Knotweed.  When I brought the cutting in for examination I learned that it was actually a native knotweed, Polygonum virginianum, aka Jumpseed or Virginia Knotweed.  It is also known and sold as Persicaria virginiana and Tovara virginiana.  This particular specimen had dark green leaves; however many plants have a red chevron on otherwise green leaves.  

This stem got beat up a bit after I pulled it out from a mass of wineberries.
I would have left it alone had I known what it was.
Of these five natives, I think Jumpseed is the most easily adapted to a landscaped garden.  In addition to the red striped leaves and more compact habit, the long flower stalks (up to 3 ft) turn from pale yellow to red as they age.   A cultivar with particularly strong red markings is called 'Lance Corporal'.  Another cultivar called 'Painters Palette' has multicolored leaves.  The biggest negative is that it can reseed vigorously.  Jumpseed does well in dry shade.  I had a client in the Boston area with a large patch of these growing on the north side of the garage in full shade.   I will keep an eye out for more of these so that I can see how the red color develops on the flower stalk.

Thursday, August 8, 2013

Lessons from my Collards

An isolated collard plant looks
relatively healthy.
I've been trying to manage my vegetable garden with as few chemicals as possible.  I have been relying on companion plantings and predatory insects to help with the number of pests feeding on the vegetable plants.  I have also left some nearby areas unmown as habitat for predators.  In addition I have a jug of soapy water to collect some of the beetles, stink bugs (BMSB) and Harlequin Bugs.  The Harlequin bugs feed on members of the mustard family, this means the collards and arugula in my garden.  The arugula show little damage, but the collars have taken a beating.  This bug sucks the sap from the plants, leaving disfigured foliage behind.  The cabbage moth caterpillars have also had a field day, eating away at the damaged leaves.

The other day I noticed that some of the collars looked much better than the others.  These were the ones located at the end of the row and one that had been accidentally planted away from the rest.  It appears that by planting these leafy greens closely together the feeding insects can go easily from one plant to the next with little exposure to predators.  Access to the plants on the edges requires more work and more risk.  This is a general problem when planting monocultures.  While they are easier to maintain and harvest, they are susceptible to mass attacks by pathogens or predators (herbaceous) that can easily jump from plant to plant.

The Collards in the row have taken a lot of damage.  The Chard (red stems) is in pretty good shape.
Next year I will space my collards out into short rows of 3-4 plants surrounded by plants from a different family, which should have a different set of pests.  This year I have a long row of Swiss Chard flanking the collards.  I have been very impressed by the performance of the Swiss Chard 'Bright Lights'.  They seem to have fewer pests and the plants have been providing a long season of harvest.  By just picking the outer stems, a fresh crop will be generated from the center.   

This Wheel Bug is just hanging out on the top of an Evening Primrose, Oenothera sp.
Maybe it will grab a nearby Japanese Beetle.
Since I am depending on natural predators for pest control, I have been trying to learn which ones are out there.  One of the more frightening looking species is the Wheel Bug.  I've shown photos of the nymphs before.  Now the adults are showing up.  These beneficial insects can deliver a painful bite if annoyed, so I have been admiring them with my eyes only.

The pupae of a parasitic wasp have been feeding on this Horn
Worm for a while.  It is starting to shrivel up.

A few weeks ago I started seeing the Tomato Hornworm on the tomatoes.  The first few I plucked off and squished.  About the 3rd week of July, I noticed that they were carrying cocoons of a parasitic wasp.  Now I leave these in place so that the wasps could come to maturity.  Since that time I have only seen a couple of worms that were not infected by these wasps.

Looking out the second floor window I noticed this ground beetle.  I have determined what species this is, but these large (>1 inch) beetles eat other insects and their eggs.  These are found primarily undercover in the leaf litter.  
Don't know why this beetle is patrolling the pool cover.
The Chinese Chestnut leaf is for a sense of scale

This moth shown on an an Agastache
measures about 1 inch long.

This last insect is not a predator in the normal sense.  The Ailanthus Webworm Moth, native to tropical parts of the Americas, is a useful pollinator. What I like about it is that it's larva feed heavily on the invasive Ailanthus altissima (Tree of Heaven).  The natural food source for this insect are trees of the Simarouba genus.  It turns out that Ailanthus is a member of the same botanical family and this is close enough for these webworms.  This insect does not overwinter too far north of Florida.  I never thought I would say, YEA! for a webworm.