Our Spring season this year was full of contrasts. There were chilly days that felt like we were back in Winter and other days that were downright hot! Looking back, we have probably always had these anomalies, but it seems more pronounced lately.
Seasons and Phenology
Phenology can help us track how our seasons are progressing, but it can be tricky to know when we should focus on tracking these changes. I did some research and discovered that each season begins twice. National Geographic Seasons are defined by meteorological and astronomical changes, which are based on the earth’s position on its orbit around the sun. Meteorological seasons are based on annual temperature cycles. The calendar year is divided into 4 seasons that last 3 months each and are based on the annual temperature cycle.
- Spring: March-April-May
- Summer: June-July-August
- Fall: September-October-November
- Winter: December-January-February
Let’s see what has changed since our Spring observations on March 6th.
Photos taken June 4th:
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- Angelina Sedum
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- Rose Campion
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- Serviceberry tree
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- Redbud tree
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- Trumpet vine
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- Catmint
When should I plant?
As gardeners, we know how excited we are when we have a few warm, sunny days. Most of the nurseries are selling plants and maybe we could just get a couple and plant them since it’s so warm out. However, most nurseries have signs posted stating the earliest date to plant. This is based on phenology of course so it’s best to make sure you aren’t pushing the recommended dates. I admit I succumbed to this temptation as I do every year. The result was some totally dead plants, some frost bitten, and another trip to the nursery. If you are in doubt, wait till it’s “safe” to plant…nature always catches up! We have also had an extremely windy spring which can beat up tender plants that are starting to develop. I always enjoy walking around my gardens and noticing new growth. Sometimes in the space of a couple days, some plants appear to grow several inches. For more guidance check out these articles: Northern Gardener or U of M Midwest calendar.
Pests and Phenology
This time of year, you might also see evidence of pests that are attacking your plants and leaving traces of their presence. Phenology can help us predict what pests might be common and help us protect our plants. My Interrupted Ferns have evidence of Sawfly larvae damage, and my newly planted Coral Bells show their frass on its leaves. This Extension article gives information about sawflies and some remedies.
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- Severe chewing damage from pests leaves garden foliage looking skeletonized.
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- Small black specks of frass left behind on leaves signal active insect pest presence.
Trees, Allergies and Phenology
For those who suffer from allergies, this season is full of irritants that can affect your comfort. The seeds from trees are dancing, twirling, and floating through the air to find a place to plant themselves. Cottonwood trees start to send out their seed from late May through June, and it can look like snow on lawns. Birch trees produce Samaras full of tiny translucent envelopes containing a seed, maple trees have helicopter seeds that spin themselves into the ground. Pollen is part of phenology, and it can affect people in many ways. You can find more information at this site: Phenology and pollen.
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- A weathered birch tree catkin rests on a dark wooden deck.
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- Twin maple seed samaras, often called “helicopters,” resting on wooden decking.
Phenology as a Tool for Learning
Keep observing and learning. Summer has just begun and it’s fun to see all the seasonal changes in our environment. Describe what you observe, the date, and take a photo to add to your own log!
By Val McGruder, Hennepin County Master Gardener Volunteer
Feature photo by Ramona Šēnfeld on Unsplash