Extension doesn't collect information about plant suppliers (such as what nurseries grow or stock) or make recommendations for particular businesses, but in general, Maryland nurseries don't stock cranberries regularly or widely since they are fairly scarce in the wild in our area, and they prefer cooler climates. Maryland does have two native species, Large Cranberry (botanical name Vaccinium macrocarpon) and Small Cranberry (Vaccinium oxycoccos), but both of them are state-rare because we are on the southernmost edge of their native range. The linked common names show Maryland Biodiversity Project maps, showing where that species has been found wild in the state; the linked botanical names show a similar tracking map that covers the entire U.S. and Canada, created by the Biota of North America Program. In that BONAP resource, the lime-green highlighted counties are the places those species have been documented growing wild, and the yellow counties are places where they are wild but rare.

If you find a source for purchasing plants (which might be online, where many nurseries focusing on native plants tend to be since they don't have walk-in stores), ask if the plants were propagated from mid-Atlantic populations, which at least might be more genetically tolerant of our warm summer conditions than plants sourced from more northern populations where cranberries are more widespread. Given how rare both cranberry species are down in the mid-Atlantic, we suspect most for sale will be not locally sourced, so might be more heat-intolerant than local wild individuals.

Like their blueberry and huckleberry cousins, cranberries require acidic soil to thrive, so while good drainage is one condition for long-term health, they also must have enough soil acidity (a low pH) to grow well. This may entail adjusting the existing soil by using sulfur to lower its pH, or growing plants in containers where moisture level, drainage, and acidity might be easier to control. (Permanent changes to in-ground soil pH are not possible as the soil will always tend to revert to its natural state, since it is derived from the type of rock found in that area, meaning that repeated adjustments would have to be made to maintain a specific pH range over the lifespan of the plants.) Laboratory soil testing will reveal not only soil pH but also its current nutrient levels and organic matter content. Although labs probably won't have a check box for "cranberry" as the desired crop, you could select "acid-loving plants" or even "blueberries" to have the lab return recommendations for acidification or fertilization based on that requirement. Lab testing is encouraged for any garden plot soil used for growing food plants (often vegetables), given potential lead or other heavy metal contamination, though the risk of lead exposure is greater when soil is in direct contact with (or close to) the part of the plant being harvested.

Maryland Extension doesn't have specific information for the cultivation of cranberries (including variety options) since they are rarely grown by gardeners and farms in the state, but we can share resources produced by other states that might be helpful:

• University of Massachusetts: Homeowners’ Guide to Cranberry Vine Propagation (despite the title mentioning propagation, the page includes general selection and plant care information)
• Penn State's PlantVillage: Cranberry
• University of Maine Extension: How to Have Your Own Cranberry Garden

Miri