Latest Plant Selection
Pacific Dogwood (Cornus nuttallii)
Why Pacific Dogwood is declining in the wild, why it can still thrive in cultivation, and how to choose between the native species and disease-resistant hybrids.
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In-depth plant profiles, disease identification, and pest management for Western Washington.
Plant Health Care
Rhododendron Post-Bloom Care
The two weeks after bloom are the most important weeks of the rhododendron year. How to read three diagnostic signals and act before the window closes.
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Plant Health Care
Ground Beetles: The Night Shift Working Your Slug Problem
Ground beetles (family Carabidae) are the largest predator group working your soil surface in the Puget Sound lowlands. They eat slugs and slug eggs, cutworms, crane fly larvae, and root maggots, and they do it year-round.
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Plant Health Care
Mason Bees: The Pollinators Already in Your Garden
Most people think supporting pollinators means keeping honeybees.It is an understandable assumption: honeybees are the pollinators with the public relations department.
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Plant Health Care
Do Wood Chips Steal Nitrogen From Your Soil?
Wood chips don't deplete soil nitrogen. Learn how to use them effectively as mulch without harming tree health or plant growth.
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Plant Selection
Asian Pears: The Cultivar Choice Maritime Springs Make for You
Asian pears are easier to grow than European pears here, but the disease that actually kills them in maritime springs is not the one the cultivar tags warn you about. A regional cultivar selection guide built on the Hartman pollination chart and the PNW Handbook.
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Plant Selection
Blueberries: Why the Easiest Fruit Here Is the One People Get Wrong
Your soil is closer to right than you think, but the cultivar you choose and whether you address drainage before planting determines whether blueberries thrive or decline. A selection guide built on PNW 656 cultivar data crossed with soil tolerance and disease resistance for the Puget Sound lowlands.
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Plant Selection
Hydrangea Selection for the Puget Sound Lowlands
Your hydrangea will not bloom, or it scorched in the heat, or you cannot tell the nursery benches apart. Here is how to match hydrangea species and cultivar to the site you actually have in the Puget Sound lowlands.
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Plant Selection
Native Groundcovers: What Your Soil Decides for You
Native groundcovers provide ecological function, reduce maintenance needs, and create resilient landscape solutions for Western Washington gardens.
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Pest & Disease
Shothole on English Laurel: Four Causes, One Symptom, and When to Stop Worrying
English laurel shothole has four distinct causes, and only one responds to fungicide. Learn to diagnose fungal, bacterial, physiological, and copper-induced shothole, and when to leave it alone.
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Pest & Disease
Rhododendron Lace Bug
The pest most gardeners here call rhododendron lace bug is actually the azalea lace bug. How to tell the three species apart and time your response.
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Pest & Disease
Balsam Woolly Adelgid: The Silent Threat to Your Landscape Firs
Balsam woolly adelgid has been in the Pacific Northwest since 1930, quietly removing grand fir from lowland landscapes. Most gardeners have never heard of it. If you have a true fir, you should know what it is and what to look for.
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Pest & Disease
Spring Vegetable Pest and Disease Prevention: Diagnosing What Is Killing Your Seedlings
Three problems kill spring vegetable seedlings in the Puget Sound lowlands: damping off, cutworms, and slugs. Each leaves a different signature and demands a different fix. Learn to read the stem, the soil, and the damage pattern before you reach for a product.
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Biology
Flower Anatomy in Trees: From Pollen to Fruit
Tree flowers explained from the four whorls outward: perfect vs. imperfect, monoecious vs. dioecious, gymnosperm cones, wind vs. insect pollination, and what flower anatomy means for cultivar selection, fruit set, allergies, and disease management.
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Biology
How a Leaf Works: Stomata, Transpiration, and Why Leaves Fall
The internal architecture of a broad leaf: epidermis and cuticle, palisade and spongy mesophyll, chloroplasts, stomata and guard cells, transpiration, antitranspirants, and the controlled shutdown of abscission.
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Biology
How Conifer Needles Work: Why Evergreens Are Built Differently
The internal architecture of conifer needles and awl leaves: thick cuticle, sunken stomata, compact mesophyll, and the water-conservation engineering that lets conifers photosynthesize through a Puget Sound winter.
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Biology
Mycorrhizal Relationships: The Root-Fungal Partnership
The underground fungal economy that determines how trees thrive: how mycorrhizal partnerships work, what common landscape practices destroy them, and why the most effective management strategy is a list of things to stop doing.
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Arboriculture
Nurse Stumps and Nurse Logs: How Dead Wood Grows New Forests
Nurse stumps and nurse logs are the primary way old-growth forests regenerate in the Pacific Northwest. Learn how decomposing wood grows new trees, what stilt roots and colonnades reveal about forest history, and how to bring the same ecology into your garden.
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Arboriculture
Structural Pruning: The First Five Years That Define the Tree
How to prune young trees for storm resistance, structural integrity, and decades of trouble-free growth in the Puget Sound region.
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Arboriculture
Topping: The Harmful Pruning Practice That Persists
Walk through any Western Washington neighborhood in early spring, and you'll spot the evidence: trees that look like they've been given blunt haircuts,
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Site Assessment
Tree Damage from Construction: What You Cannot See
Two years ago, your contractor promised you the big Douglas-fir would be fine.The tree had shaded your house for forty years, and the remodel was necessary.
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Site Assessment
Frost Cracks: Why Your Tree Split Open Overnight
Frost cracks are radial bark separations in tree trunks caused by rapid temperature fluctuations. Learn how to prevent them and what to do if they occur.
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Site Assessment
Circling Roots: What Happens When You Plant a Pot-Bound Tree
You walk into your local nursery in the Puget Sound region and find a 15-gallon Douglas-fir or Japanese maple.
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Site Assessment
Right Tree, Right Place
Selecting the right tree starts with understanding your site conditions: light, water, soil, exposure, and space. Match these to the tree's requirements.
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Cultural Practices
Spring Bulb Foliage: Why the Ugly Phase Is the Most Important One
The six weeks after bloom are when next year's flowers are made. Here is why spring bulb foliage matters, what kills re-bloom, and how to design plantings so the ugly phase never bothers you.
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Cultural Practices
Pruning Fig Trees for the Puget Sound Lowlands
If you have been pruning your fig tree the way the internet tells you to and wondering why you get leaves but almost no fruit, the problem is not your tree.
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Cultural Practices
Spring Vegetable Planting by Soil Temperature
Soil temperature controls seed germination and transplant survival in spring. Know the minimum soil temperatures for your vegetables.
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Cultural Practices
Early Spring Lawn Care: What Your Puget Sound Lawn Actually
National spring lawn advice assumes winter dormancy. Puget Sound lawns skip that step. Here is what to do about moss, compaction, and clay soil damage instead.
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Concept
The Maritime Edge: Observing Coastal Ecosystems from Northern California to Willapa Bay
A coastal drive from the redwoods to Willapa Bay reveals how wind, salt, and fog shape plant communities, and why the invasive species you see on the Oregon coast are already in your Puget Sound neighborhood.
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Concept
Reading the Landscape: What a Desert-to-Rainforest Drive Teaches About Climate and Plants
A 1,200-mile drive from the Bonneville Salt Flats to the redwood coast reveals how climate shapes plant communities, and how to read the same patterns in your Puget Sound garden.
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Concept
Growing Degree Days: Reading Plant Development
Growing degree days are the accumulated heat units that drive every biological event in your landscape. HortGuide uses base 32°F for maritime climates.
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Concept
What sp. and spp. Mean (and Why It Matters on a Plant Tag)
You are reading a pest profile, a nursery tag, or a soil report and you hit it: *Otiorhynchus* sp.Or maybe *Otiorhynchus* spp. One *p* or two.
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Soil Science
Soil pH: What Your Number Means and When to Change It
Your Puget Sound soil is already acidic, and most of the time that is exactly right. Learn when pH actually needs changing, which amendments work on which soil types, and how to stop chasing a number.
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Soil Science
Understanding Your Soil: Texture, Drainage, and What They
You dig a hole for a new shrub in April and the bottom fills with water.You wait two weeks, try again, and get the same result.
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Soil Science
Soil Compaction: The Number One Urban Tree Stressor
Soil compaction reduces root growth, drainage, and water availability. Learn how to identify compacted soils and improve them for tree health.
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