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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 2005

May 31 First day of flower for Galium triflorum (fragrant bedstraw) UWGB.
May 30

First day of flower for Hydrophyllum virginianum (Virginia waterleaf) and Prunus serotina (Black cherry), UWGB (Kathy Groves).

First day of flower for Poa pratensis (Kentucky bluegrass), City of Green Bay.

Tragopogon dubius (Yellow goat's-beard) in flower, Allouez. I may have missed the start of this one while I was out of town, but it was after May 26 and was well into flower by May 30.

Rhamnus cathartica (European buckthorn) in flower, Allouez

First signs of the Plum curculio on apples in my back yard. Green Bay, WI (Dave Parsons).
[note: The Scientific name of Plum Curculio is Conotrachelus nenuphar. This insect attacks a variety of other trees and shrubs in addition to plums. They may be a serious pest if large numbers attack developing fruits, GF]

May 28 First day of flower (pollen released) Pinus sylvestris (Scotch Pine, planted individual), UWGB (Kathy Groves).
May 26

First open flowers for Euonymus europaea (European spindle-tree), City of Green Bay.

First date of flower for Polygonatum pubscens (Solomon's seal), Streptopus roseus (rose twisted-stalk), Baptisia bracteata (cream wild indigo), Euonymus alata (winged burning-bush), UWGB.

May 25 First Monarch butterfly I've seen this year, Kenosha County.
May 24

First open flowers for Vitis riparia (river grape), City GB.

An Acer negundo (box elder) branch that I marked earlier this spring has already grown 20 cm in length.

First report of Tiger Swallowtail butterfly, Forest County (Heather Gentry). I saw one in far SW Wisconsin about May 18 (Gary Fewless).

May 23 First report of Pearl Crescent butterfly, Door County (Nick Walton).
May 22 First Flowers open for Cornus stolonifera (red-osier dogwood), UWGB.
May 21 Prunus virginiana (choke cherry) in flower, UWGB.
May 20 Maianthemum canadense (Canada mayflower) in flower, UWGB (Kathy Groves).
May 16 A first spring male summer tanager was feeding at the orange halves we have out for orioles. He returned several times during the evening hours, and I managed to get a few OK photos (attached). This is a new yard bird for us, and also a life bird for Wisconsin, Town of Cooperstown, northern Manitowoc County (Joel Trick).
May 15 Comandra umbellata (toadflax) in flower, UWGB (Kathy Groves).
May 14 Geranium maculatum (wild geranium) UWGB (Kathy Groves).
May 13 Lonicera xbella (showy bush honeysuckle) has a few open flowers today, UWGB.
May 12

Low temperatures in Green Bay fell deep into the 30's yesterday and today (33 and 34 F respectively). Rhinelander fell to 29F on the 11th and 27 today. Needless to say, the development of spring flowers has slowed considerably.

May 10 Some Syringa vulgaris (lilac) are in flower, Brown County, Town of Scott.
May 08 The first Trillium grandiflorum (large white trillium) flowers are fully open, UWGB.
May 07 Zanthoxylum americanum (prickly ash), Salix fragilis (crack willow), Salix exigua (sandbar willow) in flower (pollen dispersed), UWGB.
May 06

The last two nights have seen the heaviest migration of the year to date, and many bird species are being reported throughout the state. Yesterday I saw my first clay-colored sparrow; new arrivals at our house this morning included Baltimore oriole and Nashville warbler. Town of Cooperstown, Manitowoc County (Joel Trick).

Prunus pensylvanica (pin cherry), Ribes rubrum (garden red currant) and Fragaria virginiana (wild strawberry) in flower, UW-Green Bay. Cardamine diphylla and C. concatenata (toothworts) are beginning their peak flowering period.

The over-winter damage to plants on the arboretum by whitetail deer appears to be worse this year than any time in the recent past. They fed heavily on species that they normally eat only sparingly, including Willows (Salix sp.) and American black currant (Ribes americanum). This may be a result of having reduced their favorite species to very low levels -- such as these Thuja occidentalis (white cedars).

May 05
Amelanchier sanguinea (Juneberry), Viola pubescens (yellow violet), Ribes cynosbati (eastern prickly gooseberry), Prunus americana (American wild plum) and Prunus nigra (Canadian wild plum) in flower, UWGB
Viola pubescens

The pleasant odor of Populus balsamifera (balsam popular) is conspicuous on UWGB's Cofrin Arboretum, as the leaves begin to open. The common name is based on the similarity of its smell to that of balsam fir. This is one of my favorite fragrances. Many people associate this smell with spring in the forests, without recognizing its source.

Taraxacum officinale (dandelion) has been in flower since April 4, but it is just now entering its peak flowering period in the City of Green Bay.

May 04

At last, a sunny day with somewhat warmer temperatures. Sambucus pubens (red elderberry) and Ribes odoratum (golden currant) have begun to flower, UWGB.

First report of 13-lined ground squirrel, UWGB.

Spring azure butterfly observed, UWGB.
Populus tremuloides (quaking aspen) is leafing out quickly.--->

May 03 Erythronium americanum (yellow trout-lily) and Viola conspersa (common blue violet) in flower, UWGB. Cold weather persists, but this day included enough sunny sky to evoke a few open flowers.
May 01

Cardamine diphylla (= Dentaria diphylla, broad-leaved toothwort) in flower, UWGB.

In a drive through northeastern Wisconsin (Oconto, Forest, Vilas, Florence and Marinette counties) I experienced nearly every kind of weather possible, except for tornados. Numerous snow flurries were interspersed with rain, sleet, brief periods of sunny sky and two episodes of hail. Some snow flurries were intense enough to reduce visibility for a few minutes and on occasion the road shoulders acumulated enough snow to whiten them. Nevertheless the local residents insured me that the wood ticks are out. Spring will advance quickly as soon as sunny, warm days return.

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Last updated on May 20, 2015