Please enjoy our quarterly newsletter with information about upcoming events, program updates and native plant tips!

Summer began with the solstice on Thursday, June 20, 2024. The season of sun, vitality, action, outdoor activity, and our gardens exploding in color and edible plants. According to the Farmer’s Almanac, The solstice marks the official beginning of summer in the Northern Hemisphere, occurring when Earth arrives at the point in its orbit where the North Pole is at its maximum tilt (about 23.5 degrees) toward the Sun, resulting in the longest day and shortest night of the calendar year. On the day of the June solstice, the Northern Hemisphere receives sunlight at the most direct angle of the year. The term “solstice” comes from the Latin words sol (sun) and sistere (to stand still). The June solstice is significant because the Sun reaches its northernmost point in the sky at this time, at which point the Sun’s path does not change for a brief period of time. These seasonal shifts and changes are vitally important to learn in order to be a good gardener, listening to the seasons, and to the intelligence of nature. You can always read more about the summer solstice here: The Old Farmer's Almanac

The PNW has a New Planting Zone

On November 15, 2023, the United States Department of Agriculture (USDA) issued an update to its Hardiness Zone Map, and our location went from Zone 8b to 9a. The map has long been a useful tool for gardeners to determine which perennial plants are likely to survive their region’s coldest temperatures. Zones are assigned based on the average annual minimum winter temperature of a location and change in five-degree (Fahrenheit) increments. The map is generally updated every 10-12 years. The goal of the map is to provide an analytical estimate of which plants should survive the average lowest temperature in each area. But, as with all things gardening, there are few absolute guarantees. This does mean the PNW can likely grow some new and different plants that can overwinter more successfully now.  But, this could also signify that there will be more pests that survive through the winter. You can read more here: USDA Zone Changes - How Does this Affect NW Gardeners? - Sky Nursery

Urban Heat Islands and the Cooling Power of Plants

Summer has arrived, and summers are getting hotter and hotter across the globe. Climate change is bringing steadily rising temperatures and those effects are felt most acutely in urban settings due to the alteration of the natural environment. 2023 was the hottest year on record globally, as the year had six record-breaking months and two record-breaking seasons. Because cities have lost green space and vegetation, they create their own microclimates and are much hotter than surrounding rural areas within the same type of ecosystems. When vegetation is cleared and replaced by asphalt, the dark surfaces absorb solar radiation and store heat during the day then release it at night. The land area never has a chance to cool down at night, as it would naturally. This is referred to as the urban heat island effect. The urban heat island effect can be deadly for certain communities in urban settings, such as the elderly, those with pre-existing health conditions, people experiencing homelessness, immigrants, outdoor workers, and first responders.

We tend to understand that trees provide shade from their canopy, but shrubs and vegetation provide a natural cooling effect from a process called evapotranspiration. Plant evapotranspiration increases the air humidity, and creates a buffer against the urban heat island effect. Climate mitigation strategies can enhance community resilience against climate change impacts while contributing to human and non-human well-being. The escalating intensity and duration of heat events in cities are increasing the importance of sustainable, nature-based infrastructure designs that respond to the unique challenges of climate change in the urban area. Looking to what already exists in nature as inspiration for ecologically based solutions can be a cost-effective, sustainable, and smart way to mitigate rising heat in built environments, as the design of nature is vastly intelligent.  Examples of nature-based solutions include rewilding or re-greening initiatives, which add urban green space, urban farming and gardening, tree planting projects, native ecosystem restoration, the use of green roofs and vertical green walls, the removal of asphalt and replacement with permeable surfaces, watershed enhancement, and the use of bioswales and rain gardens. One of the most simple acts that we all can do to restore and enhance the urban ecosystem is simply to add and enforce greenspace with a wide variety of densely planted native plants and trees. 

Native Plant to Know

Showy milkweed, or Asclepias speciosa, is a native tall flowering perennial plant that can grow to 1 1/2-3 ft. tall, with large, oval, blue-green leaves and showy, spherical clusters of rose-colored flowers. It is the host plant to the Monarch butterfly, and very attractive to pollinators. Showy milkweed may be better suited in garden settings because it spreads less aggressively than Common Milkweed. Showy Milkweed is common through its native range which extends mostly west of the Mississippi River. In its native range, it can be found in prairies, savannas, and other open spaces. It does not tolerate shade, but can handle most soil types. It is a beautiful addition to your native pollinator garden!

Invasive Plant to Know

Tansy Ragwort

Tansy ragwort, or Jacobaea vulgaris, is a toxic, invasive plant found in the PNW. It is Native to Northern Africa, Asia, and Europe. It is toxic to humans and livestock. According to the Washington State Noxious Weed Control Board, When prevalent, tansy ragwort is one of the most common causes of poisoning in cattle and horses, caused by consumption of the weed found in pasture, hay, or silage. Milk produced by affected cows and goats can contain toxins. Tansy ragwort is a tap-rooted biennial and sometimes a perennial herb growing up to four feet tall. It produces flowerheads that are flat-topped clusters. Disturbance, such as mowing, may cause the plant to behave as a perennial, appearing year after year. May be confused with Common St. Johnswort (Hypericum perforatum) and Common Tansy (Tanecetum vulgare). Tansy ragwort is readily found in open, disturbed areas such as roadsides, in pastures, fields, and cleared forested areas. You can read more here: Washington State Noxious Weed Control Board

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