Invasive Control - Sprouts from Bird Droppings

I believe I have reached the maintenance stage in my efforts to control invasive shrubs at Blue Jay Barrens.  After eliminating all of the large, fruit producing specimens, I spent a couple of years dealing with masses of root sprouts surrounding the dead stumps.  Now I deal primarily with newly arrived two to three year specimens.  The Autumn Olive in the photo above shows what I typically find during my searches for invasive shrubby species.

Birds are the primary transport mechanism bringing seeds of invasive plant species onto the property.  Seeds passed through the gut of a bird arrive via bird droppings.  The bird’s digestive process softens the hard seed coat, making it a high likelihood that the seeds will germinate come the next growing season.  Seedlings arising from this type of process are usually found growing in a closely packed clump only a few inches across.

A typical clump consists of 8 – 12 individual plants, identifiable here by the light colored stumps that remained after the tops were removed.  The seeds are most often deposited in the fall.  By the time the seeds germinate in the spring, they have been separated slightly through the action of the soil fauna feeding on the non-living portion of the bird dropping, along with climatic factors such as rain, wind and frost-heave. 

I sometimes find first year seedlings, but they are hard to see because their height rarely exceeds a few inches.  It’s more usual to discover the two or three year old clumps.  A plant that reaches only six inches one year can easily grow to three feet by the following year. 

The seedlings within a clump are in fierce competition with each other.  Only those that make the most efficient use of the resources within their root zones will survive.  Within each clump are one or two stronger stems that overtop the others.  Stems on the outskirts of the pack frequently grow horizontally along the ground and form roots away from the group.  Here they can develop with less competition and increase their chances of survival.

The seeds in this group failed to disperse much beyond the limits of their original deposition.  Horizontal growth was the only way for many of the plants to access sunlight.

I don’t know how many thousands of seeds are brought into Blue Jay Barrens by birds each year.  It’s usually not difficult to find fresh seeds on the ground in areas frequently used by birds for feeding, roosting or loafing.  A good example is this pan of fresh water that I keep near my bird feeding station.

On the deck beside the pan is an assortment of seeds left behind by birds coming in to drink or bathe.  From late summer through mid-winter, new seeds are added daily to the collection.  When I empty the old water, done once or twice each day, there are always a few seeds in the pan.  Not all of these seeds come from invasive species.  The majority are Eastern Red Cedar, a native that happens to be a threat to open grassland and prairie.  There are enough invasive seeds though, to make alien shrub seedlings a permanent fixture here.  Fortunately, there are no more invasive shrubs at Blue Jay Barrens that are mature enough to produce fruit.  I am no longer contributing to the problem, I am just dealing with it.

Draba & Leavenworthia Blooms

Here we are again with two of my favorite plants, Leavenworthia uniflora and Draba cuneifolia. These particular plants are some that are growing in one of the beds of my vegetable garden. I get to see them every day, and every day I am more impressed with the size and vigor of these pampered specimens. What a difference good soil and lack of competition make in the development of these species.

These two Leavenworthia uniflora plants have grown together to form one. Leaf and flower production has been compromised where the two plants collide, but even when considering that impediment it’s fair to say that each plant has produced a remarkable number of flowers. At some points there are so many flower stalks that they almost obstruct the view of the leaves below.

Each one of those flowers will produce a pod containing 10 to 12 seeds. These two plants alone will produce hundreds of seeds.

The Draba cuneifolia hardly bears any resemblance at all to the much smaller plants found growing in their typical habitat on the barrens. Flower stalks come out of the main plant from all directions.

The typical wild plants generally have a single flower stalk that rises vertically from the cluster of basal leaves. These garden specimens produce a few vertical stalks, but far more of the flower stalks grow horizontally from the bulk of the plant.

Each stalk has no shortage of blooms.

Hidden by the wreath of open flowers are clusters of new buds, some ready to open and others just beginning to form.

Each flower leaves behind a small flat pod.  Each of these pods could easily hold over 100 seeds. The flowers remain clustered at the top stock, but once a seed pod begins to develop, the stock elongates so that there is a gap between each pod.

Most of the Draba cuneifolia plants already have a dozen or more active flower stalks, but that is only the beginning for this season. Dozens more stalks are already beginning to push their way upwards. My harvest of seed from these plants should be phenomenal. That seed will go a long way in helping to expand the populations now growing on the barrens. I’m just hoping that the 20°F temperatures and possible snow forecast for this weekend doesn’t have an adverse effect on the yield.

I would offer an apology to that individual who is tired of seeing me blog about the Leavenworthia uniflora and Draba cuneifolia, but I am certain that he would never have read down to this point.

Harvesting Draba Seeds

This could pass as a Martian landscape, but it is actually a portion of the seed I harvested today from my container grown Draba cuneifolia.

The container was so crowded with Drabas that the flower stalks had woven into one great mass.  Any attempt to harvest seed from one plant caused all of the neighboring plants to dump their seed load.  More than enough seeds had already fallen back into the container, so I had to find a harvest method that could effectively remove the remaining seeds from the plants without additional losses.

The Draba seed pod is divided into two halves with a thin, semi-transparent membrane running through the center.  Seeds are arranged in two rows on each side of the membrane.  When the seeds are ripe, the two outer coverings of the pod begin to peel back at the bottom, leaving the seeds exposed.  At this point, it doesn’t take much disturbance to cause the seeds to fall free.  In the past, I have harvested seed by simply bending the plant over a small cup and giving it a couple of taps.  The seed fell into the cup and that was all there was to it.  That method doesn’t work when the tangled plants all acted as one unit.

I decided to try using my shop vac as a harvester.  My shop vac is a bagless model, so I took a clean sweeper bag and modified it to fit the inlet pipe on the inside of the shop vac dirt chamber.  Then I directed the sweeper hose towards the plants and the seeds quickly disappeared.  The shop vac is not a high end model, so the air flow past the plants was really kind of gentle and did little more than pull away loose parts.  I just hoped everything was ending up in the bag. 

 

Fortunately, the sweeper bag stayed in place through the entire operation.  I sucked in a lot of seed pod covers, along with a little bit of dirt, but it looked like there was also some seed in the collection.

A closer examination revealed plenty of seed hidden beneath the seed pod parts.

I had to cut the sweeper bag in half to remove the seeds, but I was happy with the harvest.

Draba seeds are tiny things.  That’s a normal sized nickel beside the seed pile.

This is what I ended up with after sifting the mess through a screen to separate out the seed.  That’s five grams of fine Blue Jay Barrens Draba cuneifolia seed.  I couldn’t find any figures specifically for Draba cuneifolia, but similar Draba species average about 6,000 seeds per gram.  That means there are 30,000 seeds in this vial.  I’ll be scattering this seed back on the barrens in the same area from which I originally collected seeds for my container grown population.  I think I’ve repaid that loan of a few seeds with adequate interest.

Kissing Krigias

I’ve been paying special attention to a small pot of Potato Dandelion, Krigia dandelion.  This pot contains the plants that escaped, with the help of a Chipmunk, from a much larger container of Potato Dandelions that had been established for many years.

This is what the plants looked like back in early April when I moved them from the middle of a junk pile into a pot of rich soil.  In just about every account I read of Krigia Dandelion it states that this plant is hard to transplant and grow.  That information comes from a 1963 publication by Julian Steyermark entitled Flora of Missouri in which Steyermark states “it does not transplant well and is difficult to grow.  It has been tried several times with failure in the author’s northern Illinois wildflower preserve“.  In my experience, Potato Dandelion is quite easy to transplant, especially if you are working with the dormant tubers.  It also grows with great vigor.  I think people have misinterpreted what Steyermark actually meant.  The quote seems to be saying that the plant is difficult to establish into a new, natural site.  With this I have to agree.

This is what those scrawny transplants look like now.  Potato Dandelion grows like a weed when protected from predators and relieved of competition from other plants.  If a natural site could be found that offers those advantages, there would be no stopping this plant. 

The pot was left sitting on a picnic table in a location that received nearly full sunlight.  Over 40 flower stalks emerged from the original 10 plants.  It will be interesting to see how many new tubers have been created in this small pot.

Potato Dandelion is a member of the Aster family and each bloom is a collection of individual flowers all arising from a common base.  Each flower has a single attending petal, so a count of the petals identifies the number of flowers present at the top of the stalk.  Each of these petals should be able to produce a seed.  Unfortunately, most of the flowers fail in their reproductive duties.

Pollinating insects regularly visit the flowers.  Most common are small bees and beetles.

This species of Jewel Beetle has been very common this year.  I believe this to be Acmaeodera ornata, but my references only cover about 20% of the species that could be encountered in this area, so I’m never completely sure I’ve arrived at the proper identification.  Whatever the species, the beetles were usually carrying a dusting of pollen on their bodies as they moved around the flowers.  You would think that type of activity would certainly result in some pollination.

In an attempt to increase the chances of pollination, I went out each day and forced all of the open blooms to kiss each other.  This process has got to be moving some pollen around.

So far, there have been no seeds produced, just empty husks.  Sometimes, plant species that reproduce themselves vegetatively can form large colonies of individual plants that are essentially clones of each other.  If that species needs to receive pollen from another plant in order to produce seed, that pollen would have to come from a plant that is not its clone.  It’s possible that Potato Dandelion fits that description and I’m dealing with a clone population that is basically all the same plant.  If that’s true, I may never get any seed.

Protecting the Harvest

This has been a year of many plant species deviating from their normal development cycle.  Some species flowered late, some early, some have stayed around for the whole summer and others were totally absent.  Most have had individual plants that flowered out of sync with the rest of their group.  This Prairie Dock is an example of that condition.

I’m enjoying the extended flowering period, but the rest of the Prairie Dock plants are well past this stage.

This is the time of year for seeds to be ripening.  The tall flower stalks have lost their color and the plants are busy pumping energy into the achenes that will soon dry and scatter on the wind as a promise of new plants in the future.  I plan to intervene in this natural process and gather the seeds for distribution in areas of my own choosing.

The achenes containing the seeds can be seen surrounding the central disk.  Each flower head produces about a dozen achenes and each achene contains a single seed.  I’ve read that seeds will germinate if planted while the achenes are still green, but I’ve never had any success with that method.  I won’t harvest until the entire seed head is dry.

I opened a couple of the seed heads to check on seed development.  Every achene I checked was swollen with a developing seed.  I should be able to collect plenty of seeds.  At least I will if I can keep the birds from eating them before they dry.  The almost sunflower like seeds are eagerly sought by many bird species.  Goldfinches in particular can clean out an entire stand in just a few days and they don’t wait for the seed head to dry.

In order to save some seeds, I must make them inaccessible to the birds.  I usually don’t take any action until I see some sign that the birds have begun their harvest.  The most noticeable sign, aside from the birds themselves, is bird droppings on the leaves below the flower stalks.

I place a net barrier around the portion of the seed crop that I would like to claim as my own.  The open mesh of the net allows adequate air flow for the seeds to dry.  When the bulk of the seed crop is ready to harvest, I’ll remove the net and pluck the seed heads.  When I first began doing this, I tried to cinch the net around every possible opening, but a bird would always end up inside the net.  Letting the bird out was a nuisance, so I’ve changed my methods slightly.  Now the bottom and top of the net are left open.  If a bird really wants to, it can get inside the net and later it can easily get out.  Those few birds that do go in eat so few seeds that it doesn’t make a difference to my harvest.  I also leave plenty of stalks outside the net for use by the birds.  In this way I think we all get what we want.

Bird Box Check

I’ve begun to check the bird boxes to make sure they’re in shape to satisfy any birds that are ready to begin nest construction.  Wet weather and strong west winds have left this box with a little lean to the east.  The birds won’t mind a slightly uneven floor.

The last 2011 tenants were a pair of Tree Swallows that managed to successfully fledge six youngsters.  All Tree Swallows line the nest with a few feathers, but this pair has set a Blue Jay Barrens record for the number of feathers in a single nest.

Many of the boxes are used as winter roosts by the Bluebirds.  Sometimes they choose a box containing an old nest, so I always leave a couple of boxes with nests through the winter.  Since there were no signs that this box was being used as a roost, I cleaned out the nest material and brushed out the dust with a homemade Indian Grass brush.

This box was cleaned out in the fall and has been used all winter by roosting Bluebirds.  I clean the droppings out every few weeks, so it’s easy to confirm that the box is still being used. 

Bluebirds consume a lot of fruit over the winter, so their droppings are full of seeds.  Seed coats were softened by the bird’s digestive juices, making the seeds ready to germinate.  This is part of the reason so many shrubs grow up around the boxes.  By germinating the seeds in pots, I’ve discovered that the birds feed heavily on Eastern Red Cedar, Wild Grapes, Poison Ivy, Japanese Honeysuckle, Autumn Olive, Multiflora Rose and Bush Honeysuckle.  I see a lot of those species represented in this mess.

Besides the familiar seeds, there are a few that I don’t recognize.  I think I’ll go ahead and pot these up and see what develops.  It may be a good idea to do this every year.  If there is a new invasive plant moving into the area, I bet the birds will find it before I do.  Germinating the seeds may act as an early warning system of invasion by a new exotic species. 

Late Fall Indian Grass

The weather forecasts kept predicting Thanksgiving Day to be mostly sunny. That forecast finally changed around mid afternoon when the clouds still had not parted. I was looking out over the Indian Grass field, thinking about how the frequent rains had leached so much color from the golden stalks, when sunlight suddenly engulfed the field. It really improved the mood of the day.

Wind and rain have stripped most of the Indian Grass seeds from the seed heads. Rainfall for November is already well above normal and we have yet another storm moving our way. Each storm has been accompanied by buffeting winds and most have been followed by a day of strong straight line winds. Anything not well anchored has been blown around.

Several plants have held onto florets that never managed to produce seed. These are mostly found in the patches of Indian Grass that flowered late in the season. Even in those areas though, the majority of plants managed to produce viable seed.

The seeds are now found on the ground or caught in the leaves at the base of the plants. This is where the birds will spend the winter foraging for Indian Grass seeds. On quiet winter days, you can sit in the field and hear the birds moving noisily through the grass.

As I thought about the birds, a flock of blackbirds went past overhead. The seed foragers are primarily sparrows, but the blackbirds will also make use of the field of tall grass. Sometime during the winter, blackbird flocks will move through the cedars feeding on the berries. They find the Indian Grass fields to be an ideal roosting site and will sometimes settle in by the thousands. It’s an amazing sight, but all I can think about is the thousands of cedar seeds that will be left behind in my prairie fields. Each seed represents a potential cedar tree that I will be eliminating in the future.