Spring Has Sprung in the Willamette Valley, Is It Early?
If you have been spending time outside in the Willamette Valley lately, you have probably noticed the incredible symphony of growth and blooming flowers that nature is currently orchestrating. Plants both native and introduced have been showing their colors, and awakening from their short winter slumber.
With the first day of spring being March 20, this begs the question, has spring come early this year?
In the Northern Hemisphere, the vernal equinox marks the beginning of the season. However, meteorologically speaking, true spring is considered to start on March 1 and continue through May. Some common signs that spring has arrived in the valley include: worms emerging from the ground and robins arriving to hunt them; large queen bumble bees buzzing around in search of nesting sites; ladybugs taking flight; green and red buds appearing on shrubs and trees; and flower blooms accelerating at a rapid pace. When reviewing this check list, it seems that spring may have begun as early as late January in the Willamette Valley.
So is late January outside the range of what is normal spring onset for our region?
While there are many factors to consider, local plants may provide some clues as to whether spring is truly early this year. One of the first native shrubs to bloom in our region is the Indian plum or osoberry (Oemlaria cerasiformis). Blooms were observed around Corvallis as early as the first week of February. The flowering period for this plant stretches from February to April, so nothing so unusual here.
Let’s look at another common shrub in the valley, the state flower, Oregon grape (Mahonia aquifolium). This shrub has a bloom time of April to May, yet it is currently in full bloom in parts of the valley. Maybe an indicator of early spring?
That makes one early blooming shrub (Oregon grape) and one that is still blooming within the normal range (osoberry). Let’s consider another common valley shrub, the willow (Salix sp.) Fuzzy willow catkins are a classic sign that spring has just arrived. The bloom period for willows native to the valley range from February to May. However, Hooker’s willow (Salix hookeriana), pictured below, has a bloom period beginning in April, so this particular species is showing catkins quite early.
Another example of early blooming is the red flowering currant (Ribes sanguineum), which has just started to bloom, and typically does not flower until May.
Let’s move a little closer to the ground to observe some wildflowers. Oaks toothwort or spring beauty (Cardamine nuttallii var. nuttallii) is a charismatic little member of the mustard family that grows in moist sites under forest cover. It has been has a bloom time of April to May. It is currently blooming in March, which indicates that this species is a bit early.
Snow queen (Synthyris reniformis) grows in mixed evergreen forests of the valley. It is a very early blooming wildflower, and tends to be one of the first to emerge after snow melts. Though there was no snow, this flower bloomed at its normal time in February.
In conclusion, while there are several flowers blooming within a normal range, there are many that can be considered quite early this year. The significance of this may be difficult to determine, since there are many other factors to consider, including changes in average temperature and degree days, moisture levels, and phenology of exotic plants.
So, did spring arrive early this year? You decide.
If this topic intrigues you, consider becoming a part of a growing network of citizen scientists helping to gain a better understanding of how seasonal changes are linked to long-term trends to improve planning and decision making. Check out these two programs:
- Oregon Season Tracker (OST) is a project of Oregon State University. Citizen scientist volunteers gather scientific data on precipitation and seasonal plant changes at home and other locations to share with other observers and research partners statewide.
- Community Collaborative Rain, Hail and Snow Network (CoCoRaHS) is a nationwide volunteer network of backyard weather observers measure and map precipitation in their local communities.