Every number above carries a confidence tier. These are the ones the corpus does not stand behind — estimated from general knowledge, or contested between sources. They are shown because hiding them would be the dishonest half of showing the rest.
hardiness zone — estimated
mature spread — estimated
ph range — estimated
Rules that apply to Strawberry
Promising
Do not establish Verticillium-susceptible perennials (raspberries, strawberries, stone fruit) in ground that recently hosted Verticillium dahliae — either nightshades, or a logged planting of a Verticillium host (strawberry, raspberry or other bramble, or stone fruit).
costly if ignored → warn
Mechanism: Verticillium dahliae persists in soil as microsclerotia and infects a wide host range spanning nightshades and rose family. There is no in-ground cure once a susceptible perennial is planted, so it can wilt and die from inoculum an earlier host left behind — and because the reservoir family may differ from the victim's, the same-family rotation intervals miss it.
Evidence: confirmed against 3 sources in the research-based literature.
the 3 sources
Penn State Extension, 'Bramble Disease - Verticillium Wilt' (Kathy Demchak), extension.psu.edu/bramble-disease-verticillium-wilt (read 2026-07-12): 'Verticillium wilt is caused by two common soilborne fungi (Verticillium dahliae and Verticillium albo-atrum) that have a wide host range'; 'To minimize disease, choose a planting site with no known history of this problem. Avoid land recently planted with tomatoes, potatoes, eggplants, peppers, strawberries, raspberries, or stone fruits'; 'There are no effective fungicides for management once the plants are in the ground'; 'The number of years required to eliminate verticillium, especially the resting spores from the soil, is unknown.'
UMass Extension, New England Small Fruit Management Guide, 'Brambles - Diseases', ag.umass.edu/fruit/ne-small-fruit-management-guide/brambles/diseases (read 2026-07-12): 'Verticillium attacks a wide range of plants, including potatoes, tomatoes, peppers, eggplant and strawberries. It overwinters in the soil and on plant debris. Do not plant [raspberries following these crops].'; 'Non-host crops such as corn or wheat can help eliminate the fungus if grown for at least 2 years before planting raspberries.'
Host range / persistence corroborated by the source already cited on another rule here: NC State Extension, 'Verticillium Wilt of Tomato and Eggplant' (read 2026-07-11): 'The pathogen can survive in the soil without a host for up to 10 years in the form of structures called microsclerotia'; 'affects more than 300 host families.'
remedy
Site the perennial on ground with no recent nightshades, or choose one that is not Verticillium-susceptible. Extension advises growing a non-host — corn or a small grain — for at least two years first, without claiming that clears the soil. Once the perennial is planted there is no in-ground cure.
Do not establish Verticillium-susceptible perennials where the season log records that a Verticillium host (strawberry, raspberry or other bramble, or stone fruit) previously grew — a reservoir the coarse prior-nightshades family signal structurally misses.
costly if ignored → warn
Mechanism: The same reservoir as the family-level rule — Verticillium dahliae persisting in soil as microsclerotia — but recognised precisely instead of coarsely. The family-level rule fires on a prior nightshades family, which is all a manual history checkbox can express; this rule fires on the logged planting's own species carrying the verticillium_host marker, so a prior rose family host (strawberry, raspberry, stone fruit) counts while a non-host rose family like apple correctly does not — precision the family signal cannot give.
Evidence: confirmed against 3 sources in the research-based literature.
the 3 sources
Penn State Extension, 'Bramble Disease - Verticillium Wilt' (Kathy Demchak), extension.psu.edu/bramble-disease-verticillium-wilt (read 2026-07-12): 'To minimize disease, choose a planting site with no known history of this problem. Avoid land recently planted with tomatoes, potatoes, eggplants, peppers, strawberries, raspberries, or stone fruits'; 'There are no effective fungicides for management once the plants are in the ground.'
UMass Extension, New England Small Fruit Management Guide, 'Brambles - Diseases', ag.umass.edu/fruit/ne-small-fruit-management-guide/brambles/diseases (read 2026-07-12): 'Verticillium attacks a wide range of plants, including potatoes, tomatoes, peppers, eggplant and strawberries.'; 'Non-host crops such as corn or wheat can help eliminate the fungus if grown for at least 2 years before planting raspberries.'
Host range / persistence corroborated by NC State Extension, 'Verticillium Wilt of Tomato and Eggplant' (read 2026-07-11): microsclerotia survive 'up to 10 years' and the pathogen 'affects more than 300 host families.'
remedy
Site the perennial where the log shows no previous Verticillium host, or choose one that is not susceptible. Extension advises growing a non-host — corn or a small grain — for at least two years first, without claiming that clears the soil. Once the perennial is planted there is no in-ground cure.
Hardiness zone is the correct variable for perennials, and only for perennials.
suboptimal if ignored → advise
Mechanism: Zones encode average annual minimum winter temperature, which governs whether a woody perennial survives to spring. It is the wrong quantity for an annual, which never sees winter.
THE CEILING IS A SECOND AND DIFFERENT MECHANISM, and until 2026-07-26 this rule enforced it without naming it. A zone too WARM does not kill a perennial; it fails to chill it. Deciduous fruit crops need a winter dormancy period to break bud and set fruit, so in a zone milder than a plant is adapted to it may survive and never crop. Until ISSUES #13 was decided the band was enforced at both ends; now (option E) only the cold end gates — it alone follows from the definition of the zone system — and the warm end is carried as an ADVISORY, not a refusal.
AND THE WARM END IS A CULTIVAR'S ANSWER, NOT A SPECIES', which is the honest limit of what this rule can do. Chill requirement is published per variety and varies enormously within a species, so a species-level ceiling says "the modelled range does not reach your zone", never "no plant of this kind will crop for you". So the engine offers the plant above its band and advises choosing a cultivar rated for the zone rather than refusing it — the same move invariant 3 makes for soil, applied to chill.
Evidence: confirmed against 3 sources in the research-based literature.
the 3 sources
THE FLOOR IS TRUE BY DEFINITION and needs no citation: the USDA system defines a zone AS a band of average annual minimum winter temperature, so 'a plant colder-hardy than your zone survives your winter' is the definition restated. This rule was `verified_trivially` on that basis alone until 2026-07-26. THE CEILING WAS NEVER COVERED BY IT - a minimum-temperature definition says nothing about a plant failing for want of chill - and that gap is why ISSUES #13 exists. The pointer below closes it.
OSU Extension EC 1303, 'Growing blackberries in your home garden' (Bernadine Strik), catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1303.pdf (read 2026-07-26). THE CEILING'S MECHANISM, STATED: 'Winter cold-hardy cultivars adapted to the colder regions of Oregon (such as zones 5 to 7), may not grow normally in regions of the Willamette Valley (zone 8) where winters are warmer and plants receive less winter chill.' A plant failing in a WARMER zone for want of chill - which is what this rule's upper bound enforces and what no source said until now. THE SAME PAGE MAKES IT A CULTIVAR PROPERTY: 'Even cultivars within the same type (trailing, erect or semierect) differ in fruit quality and flavor, appearance, tolerance to pests, cold hardiness, and plant longevity', and the remedy it gives is the one this rule's rejection text now repeats: 'Minimize risk by choosing types and cultivars that are adapted to your hardiness zone.' The page then publishes a table of sixteen cultivars EACH WITH ITS OWN ZONE RANGE, which is the strongest available evidence that a species-level band is an approximation. [read]
WHAT THIS DOES NOT SETTLE. The mechanism is now named, but the corpus still carries ONE band per species where the source carries one per cultivar, and 12 of 25 perennial zones have no citation at all. So the ceiling is explained without being precise. ISSUES #13 stays open on that, and the rejection text is deliberately phrased as 'the modelled range does not reach your zone' rather than as a prediction that nothing will crop.
On a new June-bearing strawberry planting, remove every blossom for the whole first season - check weekly and pinch or cut them off; flowering stops by early July. Letting first-year flowers set fruit reduces plant growth, runner production, and the size of next year's crop. Everbearing and day-neutral types are handled differently: remove blossoms only for the first stretch after planting - about four to six weeks, or until early July - then let them fruit, with first berries from August until frost.
suboptimal if ignored → advise
Mechanism: A first-year plant that ripens fruit spends its resources on berries instead of on the root system, leaf canopy and runners (daughter plants) that make up next year's bed; letting the flowers develop into berries reduces plant growth, runner production and the size of next year's crop, while removing them directs the plant's resources into a large root system and a healthy plant. June-bearers crop once a year, so the whole first season is given to establishment; everbearing and day-neutral types keep flowering, so only the establishment window is sacrificed and later flowers are allowed to fruit.
Evidence: confirmed against 2 sources in the research-based literature.
the 2 sources
Iowa State Univ. Extension, 'I planted strawberries this spring. Do I need to remove this year's blossoms?', yardandgarden.extension.iastate.edu/faq/i-planted-strawberries-spring-do-i-need-remove-years-blossoms (read 2026-08-22): 'During the first growing season, all the blossoms should be removed from June-bearing strawberries'; 'If the flowers are allowed to develop into berries, their development will reduce plant growth, runner production, and the size of next year's crop'; 'Check the strawberry plants once a week and remove the blossoms by pinching or cutting. Flower production on June-bearing strawberries should stop by early July'; 'With everbearing and day-neutral strawberries, remove all blossoms until early July. Any flowers which bloom after this period may be allowed to develop into fruit. The first berries should ripen in August and continue until frost.'
Univ. of Maryland Extension, 'Growing Strawberries in a Home Garden', extension.umd.edu/resource/growing-strawberries-home-garden (read 2026-08-22): 'For June-bearers, remove the flowers for the entire first season to direct the plant's resources into developing a large root system and healthy plant'; day-neutral - 'Remove flowers for the first 4-6 weeks after planting, and then allow plants to fruit.'
remedy
June-bearing: pinch or cut off all blossoms weekly through the first growing season. Everbearing or day-neutral: remove blossoms for the first four to six weeks after planting, or until early July, then allow the plants to fruit.
Another 109 rules in the corpus apply by situation rather than by species — rotation intervals, frost windows, sun, spacing and soil. Read the full evidence page.
Cite this page
Milpa Gardens. "Strawberry (Fragaria x ananassa)." https://milpa.garden/plants/fragaria-x-ananassa/
A garden-planning corpus: every claim states its evidence grade and links its sources on the page. Cite it with the grade, and add the date you read it.
