Illinois Invasive Plant Phenology Report - May 16, 2014

We are starting a new series here to the Illinois ISAM Blog.  From time to time, we will be reporting on the development of invasive plants across Illinois, informing readers about what is in bloom, leafing out, setting seed, senescing in different regions of the state.

Feel free to add to the knowledge by emailing chris.evans@illinois.gov and letting me know what the plants are doing in your area of Illinois.

Phenology Report for May 16, 2014
(Contributors include Cathy McGlynn, Karla Gage, Marilyn Leger, Jody Shimp, and Mike Daab)

Southern Illinois

• Princesstree, Paulownia tomentosa – Is in full bloom right now.  Mature trees are easily identified by the dense purple flowers.  Keep an eye out for this species on rocky bluffs, ridge top, barrens, and other dry disturbed sites.
•  Garlic mustard, Alliaria petiolata – Is in full seed development right now.  You could still find some flowers on this species right now, but the majority of the plants have green seed pods.  These seed pods are long, thin and are upright on the plant.  The seed pods have not yet dried, so pulling and bagging the plants is still an option for control.  Look for garlic mustard in wooded areas across the region.
•  Black locust, Robinia pseudoacacia – Is just past full bloom right now.  You can still identify this tree species by its dropping clusters of white flowers, but it is starting to be past bloom.  Some of the trees will have flowers that are starting to yellow or be obscured by emerging leaves
•  Chinese yam, Dioscorea oppositifolia – Is emerging now and starting to elongate.  With the onset of warmer weather, this species is now starting to put on a lot of growth.  Vines can be found easily now with multiple leaves.  The heart to fiddle shaped leaves can be easily identified by the purple-red coloration where the petiole meets the leaf.  This plant has not yet started to produce its bulbils (asexual reproductive structures) and likely won’t for a month or so.  Look for Chinese yam along streamsides, ditches, and other mesic-to-wet forest sites or areas with disturbance.
•  Japanese stiltgrass, Microstegium vimineum – Is germinating right now.  You can easily find young, single-lead germinates of stiltgrass carpeting the forest floor in invaded areas.  This germination will continue for a while, so control treatments that do not include a pre-emergent herbicide should be delayed for another month or so.  
•  Bush honeysuckle, Lonicera maackii – Is just coming into bloom right now.  In a week or two this species will be in full bloom. The fragrant white flowers turn yellow with age and can be found in pairs along the stems of mature bush honeysuckle shrubs.  This plant can grow in most area wooded environment.
• Winged burning bush, Euonymus alatus - Has flowered and fruits are just beginning to form.
• Chinese privet, Ligustrum sinense - Flowers are beginning to form but have not opened yet.

Central Illinois

• Callery Pear, Pyrus calleryana - Past full bloom.  A few scattered blossoms yet.
• Garlic Mustard, Allaria petiolata - Full bloom, just beginning to form seed.  Slightly further north, no seed formation in evidence
• Autumn Olive, Eleagnus umbellata - Full bloom throughout the east central Illinois region
• Bush Honeysuckle Lonicera maackii and others - Beginning to bloom to the occasional bush in full bloom
• Sweet Clover, Melilotus officinalis, M. alba - Well-formed, bushing out, forming buds
• Field Mustard, Brassica rapa - in full bloom along roadsides and in fields

Northern Illinois

• Garlic mustard, Alliaria petiolata -  is in flower in vacant lots, roadsides, yards, and in forest understories. - http://www.nps.gov/plants/alien/fact/alpe1.htm
•  Lesser celandine, Ficaria verna -  has been in bloom for several weeks and its flowers may soon die back if they haven’t already.  Several additional reports of this species have been made along trails and roadsides. - http://www.nps.gov/plants/alien/fact/rafi1.htm
• Callery pear, Pyrus calleryana - is also in full bloom in residential areas, lining parking lots, fields, and prairies. - http://dendro.cnre.vt.edu/dendrology/syllabus/factsheet.cfm?ID=132
• Japanese barberry, Berberis thunbergii -  is in bloom in many yards and in the forest understory. - http://www.nps.gov/plants/alien/fact/beth1.htm

Updates/Contributions:  

• Eric Smith reports from SouthCentral Illinois that Dames Rocket is starting to bloom and Oriental bittersweet is starting to bud
• Jim Alwill reports from NorthWest Illinois that IDOT is starting to spray teasel rosettes along the ROWs
• Mark Brown reports from Southwest Illinois that garlic mustard has fully formed seed pods, sericea lespedeza is starting to emerge, bush honeysuckle is in full bloom, and mimosa is just starting to leaf out