I've had three varieties in 15 gal pots since 2004 without repotting that give bumper crops every year. In fact I have to remove about half the fruit. I'd estimate yield at 5-10 lbs per plant. So you don't need bigger pots. They don't need repotting very often. And I don't mulch the surface. But I do fertilize about once a month and pH is 4.5 to 5. You probably need a new mix high in sphagnum peat moss. I add enough coarse compost and fine pine bark that the peat is easier to wet. So my mix feels loose wet or dry and holds lots of air. It is about 98% organic and 2% soil. I'd doesn't settle much over many years. The surface becomes a solid mat of fine roots. Others have different methods that work. But my plants are very vigorous and productive.

ray: You need more new growth this year to have a better crop next year. For 6-7 year old plants yours are pretty small. They look more like about three years old. After harvest I'd prune out the oldest growth and trim back the other growth. Even if you have to cut off most of the plant you need to force more new growth. A big part of forcing more new growth would be a good dose of fertilizer. I use complete controlled release Osmocote for acid loving plants. Apply some on top and mix in or cover with mulch. If you don't want to prune so much and want a taller plant, just apply a good fertilizer at the recommended rate on the container.

Took them to Ag station and they don't know - says it doesn't look like disease. Thought is might be Mg deficiency but said no, Medium should be fine, very rare to have Mg deficient soil here. Might just be transplant stress. Gotta wait til plant expert is in on Tues. Temps have been around 70 with lows around 60 - a few hot days, but mostly overcast with threat of T-showers though we haven't had any rain except 1/4" Monday and some drizzle today. Was really hot over the weekend but these have afternoon shade. The thing that's got me concerned is that the lowbush bluberries looked fine til yesterday when I noticed this "rust" on them. never saw that before, even last year which was extremely wet and cold spring. Definitely not transplant stress with those. Fungal infection? They are only 2-3" high and (naturally) mulched with oak leaves.

Wild (lowbush) blueberries cannot be 'tamed', they only can be maintained by maintaining their habitat. You know whether or not you have wild blueberry bushes: their size ranges from 2" to 12", and the flavor of the berries is incomparable. No other 'blueberry' tastes like the low-bush wild blueberry. Wild Maine blueberries are now offered frozen in grocery stores, the only brand that we personally know that offers true wild Maine berries is Wyman. If you have only a few small blueberry plants and if they haven't increased on their own they may need more acid soil. You can use acidifiers that are labeled for rhododendrons or azaleas but before doing so consult U.Maine Extension to learn what dilution you need. Also ask whether mulching and more sun may be necessary. My blueberries grow in very thin soil over granite, are in full sun away from trees but they enjoy the 'mulch' provided by weeds and other low berry plants (cranberries). Except for fog, dew, or rain they're never watered, so it appears that they enjoy quite dry conditions. Though commercial growers irrigate the barrens and maintain other cultural practices (spot burning in the spring), we do nothing at all and always have a decent crop. If your berries aren't dropping to the ground and seeding, it's possible that birds and animals are eating them. In that case you can reserve a few berries for propagating. For propagation advice, consult U.Maine Extension. http://www.extension.umaine.edu/topics/blueberries.htm The answers you seek regarding blueberry culture are in the appended text below, copied from: http://www.wildblueberries.com/about_wild_blueberries/ Wild Blueberries of Maine & Canada One of only three berries native to North America, the Wild Blueberry (vaccinium angustifolium) thrives in the glacial soils and northern climate found in the fields and barrens of Downeast Maine and Canada. Rich in antioxidants, Wild Blueberries have grown naturally for thousands of years. The Lowbush Blueberries Unlike highbush cultivated blueberries, Wild Blueberries are not planted. These lowbush blueberries are primarily spread by rhizomes or underground runners, which give rise to new roots and stems. All shoots arising from the same rhizome system have similar characteristics and are referred to as a blueberry clone. Wild Blueberry fields and barrens actually produce many different lowbush blueberry clones, which account for the variations in color and size that characterize the Wild Blueberry crop. Growing and Harvesting: Blueberry Growers Combine Tradition and Technology Naturally suited to acidic, low-fertility soils and challenging winters, Wild Blueberries are a low-input crop requiring minimal management. The berries are grown on a two-year cycle. Each year, half of a growers land is managed to encourage vegetative growth and the other half is prepared for harvest. In May, growers import a billion commercial bees to aid the native bee population in pollinating the barrens and fields. There are many bee species associated with Wild Blueberries, including bumble bees and honey bees. Native bees are exceptional pollinators and Wild Blueberry growers take care to preserve wild bees through conservation practices. The Blueberry Grower  Managing the Harvest After the harvest, which begins in late July and continues through August, the plants are pruned to the ground by mowing or burning. Wild Blueberries are harvested commercially only in Maine and Canada. The oldest commercial processing company dates back to 1874 and many of todayÂs independent, family-owned growers have been in the Wild Blueberry business for generations. Many Wild Blueberry crops are still harvested the traditional way, using hand-held berry rakes that were first invented in 1910. Whether hand raked or machine harvested, Wild Blueberries are sorted, cleaned and processed within hours of being picked, using state-of-the-art technology to reserve their flavor, quality and antioxidant capacity. From Fresh to Frozen Blueberries  Preserving Taste & Nutrition Growers use winnowing machines in the fields to remove leaves and twigs before the berries are washed and frozen. Wild Blueberries are individually quick frozen (IQF) using a method that allows for the fast preservation of taste and nutrition for millions of berries. IQF berries can remain frozen for over two years without loosing their flavor or nutritional value. Laser color sorters are also utilized to remove anything but the finest quality Wild Blueberries prior to packing. Modern Crop Management  Maintaining Healthy Land & Healthy Crops Wild Blueberry growers are strongly committed to best agricultural practices. They use sustainable management techniques to ensure healthy crops and to protect Wild Blueberry lands for future generations. Because Wild Blueberries are indigenous to Maine and Canada, they are naturally resistant to many native pests. Still, growers are challenged to minimize crop damage caused by environmental stressors such as disease, drought, insect damage and winter injury. Using Integrated Crop Management (ICM) and Integrated Pest Management (IPM) throughout the crop cycle, growers monitor disease and insect levels to minimize fruit destruction without harming the environment. Good luck. I hope your berries spread and flourish.