About HortGuide
Regional plant knowledge, built for the people who actually do the work.
HortGuide is a self-improving knowledge base for horticulture, anchored to the Puget Sound lowlands. Every profile, every guide, every recommendation is verified against this climate, this soil, and these conditions.
What this site does
Most plant care information online is written for a national audience and then loosely tagged with zone numbers. That approach breaks down when you need to know whether to spray copper on your cherry tree this week, or whether the leaf spots on your bigleaf maple are cosmetic or structural.
HortGuide exists to close that gap. The site covers three areas: arboriculture - caring for trees and shrubs in managed landscapes; nursery horticulture - how plants are grown, selected, and evaluated; and landscape horticulture - the design and maintenance of planted spaces. Everything is anchored to Western Washington's maritime climate.
The reference library is the backbone. It tracks host associations between plants and their diseases and pests, documents susceptibility ratings, and maps management timing to regional conditions. The guides translate that data into practical recommendations - what to watch for, when to act, and what to skip.
The Library in Numbers
Documented plant-disease and plant-pest relationships
Written By
Chris Welch
ISA Certified Arborist® · RM-1057A
I started working in greenhouses in high school. I earned my ISA Certified Arborist® credential in 1999, my Tree Risk Assessment Qualification in 2014, and a BS in Landscape and Urban Horticulture from BYU. I've worked as a production climbing arborist and an arboricultural consultant. These days I'm on the operations side of the wholesale nursery trade. I still do risk assessments and consulting, but most of my time is spent around plants moving through production.
HortGuide is my field notes. I built it to organize what I'm learning: to take the science, the extension research, and what I see every day, and put it in one place where I can verify it against real conditions. The Puget Sound lowlands are the home base, but the knowledge library covers horticulture broadly. Every profile carries a maturity rating that shows how much verification backs it. Some are well-sourced and field-checked. Others are baseline data waiting for my attention. That transparency is the point.
If something on this site is wrong, I want to know about it. The goal is to be useful and accurate, not to publish volume.
Credentials
Education
Experience
Location
How the data works
Plant, disease, and pest profiles contain verified facts - taxonomy, host ranges, lifecycle thresholds, susceptibility ratings. No opinions, no regional spin. The data stands on its own.
Guides take that data and apply regional judgment - what to do here, when to do it, and what to skip. Every recommendation is sourced, and every source is cited.
WSU Extension, Oregon State, PNW Handbooks, USDA, and peer-reviewed research. When sources conflict, the conflict is surfaced - not silently resolved.
Get in touch
Questions, corrections, or collaboration inquiries.
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