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Observations by Gary Fewless for Green Bay WI (Lat.N 44.51° Long. W 88.02° ), except as noted. For flowers lacking conspicuous petals or sepals I define "anthesis" as release of pollen by mature anthers.

May 2007

May 31

Convolvulus arvensis (field bindweed) in flower, Brown County, Village of Allouez.

Achillea millefolium (yarrow) and Lotus corniculatus (birds-foot trefoil) in flower, UWGB.

May 30

Populus deltoides (eastern cottonwood) began to disperse fruit today, UWGB.

Rosa blanda (pasture rose) in flower, UWGB.

May 29 Tradescantia ohioensis (spiderwort), and Maianthemum racemosum (Solomon's-plume; formerly known as Smilacina racemosa) in flower, UWGB.
May 28 Viburnum trilobum (highbush cranberry) and Potentilla simplex (common cinquefoil) in flower, UWGB.
May 27 Clintonia borealis (blue-bead lily) and Cornus canadensis (bunchberry)in flower, MarinetteCounty.
May 25 Rubus idaeus (red raspberry), Robinia pseudoacacia (black locust), Vitis riparia (wild grape) and Zizia aurea (golden alexanders) in flower, UWGB.
May 24

Green Bay tied the record high temperature for today at 88° F.

Tragopogon dubium (yellow goat's-beard) and Crepis tectorum (hawk's-beard) in flower, City of Green Bay.

First day of flower (anthesis) for Poa pratensis (Kentucky blue-grass) in City of Green Bay. The flowers have been at full size for at least 8-10 days, but today is the first day they have begun to release pollen (except for small numbers in unusually favorable positions, such as at the base of a south-facing wall). You may now begin to feel symptoms if you are allergic to this pollen, and many people will now report "summer colds", without knowing (or admitting) that it is a reaction to pollen. Poa pratensis is extremely common and numerous in our area, so the amount of pollen produced is very large.

Taraxacum officinale (dandelion) is mostly done flowering. There will continue to be a small number of flowering individuals throughout summer and into fall, but the big flowering display is over for the year.

May 23

Spittlebugs on plants, UWGB.

Pinus sylvestris (Scotch Pine) male cones releasing pollen.

Prunus serotina (black cherry) in flower, UWGB.

Usually the large white trilliums turn pink/rose color toward the end of the flowering season, but this year most are just shriveling up, and sometimes turning pale brown. It may be due to the relatively dry weather recently.

May 22 Saw my first monarch butterfly of the year today, along Bairds Creek, City of Green Bay (Joel Trick).
May 21

Acer saccharinum (Silver maple) fruit are now being dispersed in the City of Green Bay. The fruit are samaras--the little helicopter style objects that spin as they fall. They will drop some immature fruits earlier, but these are now full-size and in considerable numbers.

Pinus nigra (Austrian pine) male cones are releasing pollen, UWGB.

May 19

Lupinus perennis (wild lupine), Hydrophyllum virginianum (Virginia waterleaf), Trifolium repens (white clover), Podophyllum peltatum (May-apple), Erigeron philadelphicus (daisy fleabane) are in flower.

I received my first mosquito bite today on UWGB. I have been seeing them since 5/11 and even brushecd a few off before today, but this is my first bite. UWGB seems to run a bit later on mosquitos than many surrounding areas.

I saw a Tiger Swallowtail butterfly on UWGB today.

Carp are spawning noisily in Green Bay (I may well have missed the start).

May 18 Hesperis matronalis (dame's-rocket) in flower UWGB. I've seen some earlier elsewhere, but this is my regular location.
May 17 Euonymus alata (winged burning-bush) in flower.
May 16 Maianthemum candense (Canada Mayflower) in flower, UWGB.
May 15 Cornus stolonifera (red-osier dogwood)and Pinus banksiana (jack pine) in flower, UWGB.
May 14 High temperature of 88° F in Green Bay (record high for this date is 89 in 1991). Average high for this date is 67° F.
May 13 Polemonium reptans (Jacobs-ladder) in flower.
May 11 Cerastium arvense (field chickweed) in flower, Brown Count, Town of Suamico.
May 10

First open flowers on Lonicera X bella (showy bush honeysuckle). Silene latifolia (bladder campion) also in flower.
First day for Fragaria virginiana (wild strawberry). I suspect that there were earlier flowers on other sites, but this is for a fixed site that is monitored every year.

First day for release of the fruits of Populus tremuloides (quaking aspen). This is similar to the "cotton" that is released a little later by Populus deltoides, our eastern cottonwoods. Populus deltoides doesn't start to release their "cotton" for about 3 weeks after Populus tremuloides starts. The cotton is really just a tuft of hairs attached to each seed to aid in wind dispersal of the seed.

Nineteen species of warblers at Point au Sable today, along with two Orchard Orioles (male and female), Brown County (Joan Berkopec).

May 09

Toads (Bufo americanus) still "singing" vigorously on UWGB campus (began there 04/30).

New species in flower today: Phlox divaricata (wild blue phlox), Maianthemum stellatum (starry false Solomon's-seal, formerly known as Smilacina stellata), Geranium maculatum (wild geranium) and Crataegus mollis (downy hawthorne).

May 08

First fully open flowers of Prunus virginiana (choke cherry), Brown County, Allouez,

First fully open flowers for Actaea rubra (red baneberry ) and Berberis thunbergii (Japanese barberry, alien).

The forest canopy is still not filled in, but you can definitely feel the effect of the small, emerging leaves in Mahon Woods on the Cofrin Arboretum (UW-Green Bay campus).

I saw my first Baltimore Oriole today as well as a Ruby-throated Hummingbird at the lilac flowers, City of Green Bay (Dave Parsons).

Some early plants are now done flowering on UWGB, including Sanguinaria canadensis (bloodroot) and both Erythronium (trout lilies) species. That is to say that they have lost heir petals. They will continue to develop fruit for several weeks. Cardamine douglassii (purple spring-cress), Cardamine concatenata (cut-leaved toothwort) and Cardamine diphylla (broad-leaved toothwort) are also nearly done flowering.

May 07 First day of flower for Convallaria majalus (lily-of-the-valley), UWGB.
May 06

Today is the first day of fully open flowers for Malus pumila (apple) and Syringa vulgaris (lilac), UWGB.

Today we had our first returning Baltimore Orioles, Rose-breasted Grosbeak and Indigo Bunting, Town of Cooperstown, Manitowoc County (Joel Trick).

May 0 New arrivals today included White-crowned Sparrow, Black & white Warbler and Ruby-throated Hummingbird, Town of Cooperstown, Manitowoc County (Joel Trick).
May 03

Thalictrum dioicum (early meadow rue) and Ribes Missouriense (Missouri gooseberry) in flower, UWGB.

West Virginia White butterflies flying in Forest County.

May 02 Fraxinus pennsylvanica (green ash), Ribes americanum (American black currant) and Salix exigua (sand bar willow) in flower, UWGB.
May 01

A little rain overnight and in the morning (about 0.75 inches total) was much needed in Green Bay. We've had only about an inch in the last 19 days, and fire dangers were very high farther north.

Populus tremuloides (quaking aspen) and Acer negundo (box elder) are leafing out rapidly on the UW-Green Bay campus. Among the shrubs, Lonicera xbella (showy bush honeysuckle) and Ribes americanum (American black currant) are conspicuously leafing out.


Two Red Admiral butterflies (Vanessa atalanta) in flight and several blossoming wild plum (Prunus americana), Cofrin Memorial Arboretum (Nick Walton and Jenna King).

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Last updated on August 7, 2014