Normally we think of rust as something that deteriorates metal, but a number of different fungal rusts can affect plants in the garden. Rust disease can affect corn plants, cedar trees, and even blueberry bushes. Just like the broad range of plant species that can be plagued by rust, there are a number of species of rust fungal spores floating around and ready to infest your garden. This article will focus on leaf rust of blueberry.
Blueberry leaf rust on the top of a leaf. Photo Credit: Philip Harmon, University of Florida/IFAS Extension.
Leaf rust of blueberry in Florida is caused by the fungus Pucciniastrum vaccinii. Although the common name of the disease is “leaf rust”, the disease can also infect the stems and fruit of blueberry plants. The disease causes small, round spots visible on the tops of leaves. Spots will multiply and the leaves will eventually yellow and fall off. Young stems and green fruit can also become infected as the disease progresses. Bright orange lesions will form on stems and fruit as the thousands of microscopic spores conjoin. The clusters of spores are easily wiped or washed off of plant material. When spores dry out, they become airborne and can be transferred to nearby plants.
Blueberry leaf rust on fruit. Photo Credit: Philip Harmon, University of Florida/IFAS Extension
The rust fungus thrives in hot, humid, wet conditions. A number of cultural practices can be adopted to reduce disease progression and survival.
Disease persistence can be reduced by limiting the amount of water that contacts the plant leaves. Water the base of plants or install drip irrigation for your bushes rather than watering from overhead. If overhead irrigation is the only option, then water plants in the morning rather than in the evening. This allows the leaves to dry out over the course of the day.
Removal of approximately 25% of the oldest canes in late winter before spring growth begins will stimulate the production of new canes and should result in plants with canes of different ages and will provide a good mix of vigorous branching and fruit production. Moderate summer pruning can also improve yield and shoot growth. When pruning, cut out vigorous shoots that are growing well beyond the desired canopy height and are in the interior portion of the bush. This will promote a more open growth habit and help with air circulation on the remaining plant material. Some vigorous canes developing from the ground and growing on the outside of the bush can be topped to stimulate branching and flower bud formation.
Pine bark mulch helps with establishment of young plants and helps keep soil pH low in existing plantings. A layer of aged pine bark 3 inches deep extending about 2 feet out from the plants will provide a good growing medium for surface feeder roots. Pine straw can be used if pine bark is unavailable. Mulch also moderates soil temperature, helps keep weeds at bay, and adds organic matter to the soil. Make sure to keep mulch raked back about three inches away from the plant canes to provide good air circulation to the roots.
Hopefully this article has given you some tips to have a good blueberry crop for years to come. For more information on growing blueberries in Florida, please visit the University of Florida/IFAS EDIS Publication: Blueberry Gardener’s Guide.
Every winter season in the Florida Panhandle is different. It can be wet or dry, frigid cold or unseasonably warm. We may have early frosts and early springs, or cold snaps in late march after fruit trees flower.
While we cannot determine the exact time to prune the dooryard fruit trees in our rather variable region, here are some tried and true guidelines for pruning the most popular edible garden plants in northwest Florida.
Blackberries are unusual in that they do not build a large structure and fruit for years on the same branches (in general). They actually fruit on previous years’ growth which then die after fruit production. The canes that produce fruit are called the floricanes. As the floricanes are producing fruit, the blackberry plants are growing primocanes. These are the new canes that will produce fruit for the next season. By then, these canes will have matured in to floricanes. A few new blackberry cultivars exist that produce fruit on new growth as well, but most Florida adapted cultivars are of the standard type. For pruning purposes, it is best to remove the floricanes just after fruiting, but be sure not to cut the new growth (primocanes) because that wood will bear next year’s fruit. For more information about the blackberry, please see publication HS807.
With blueberries older canes need to be removed to make room for younger, more productive canes. When a plant reaches four to five years old it is permissible to remove about 1/4–1/5 of the oldest canes each year which amounts to about one to three of the oldest canes. Performing this task will ensure that no cane is more than three or four years old. Thus, blueberry plantings will be in a constant state of renewal and not become excessively woody and nonproductive. To keep plants from becoming too tall, mature plants can be topped in the summer directly after fruit harvest. Removal of a few inches to a foot, depending on the cultivar, will stimulate the new growth that will bear the next year’s fruit. See CIR 1192 for more information
Temperate Fruit Trees
Pruning of temperate fruit trees (Peaches, Apples, Pears, Persimmons) should be done during the winter dormant period in most cases. This period, generally between December and February allows for some latitude. Pruning later in the dormant season is better in most seasons since trees are more susceptible to freeze damage after pruning, and pruning stimulates the growth of the trees. In Northwest Florida, a February pruning is usually most desirable, depending on the season (namely average high temperatures). Pruning for shape is also done in the summer months if necessary. This task should be limited to removing excessive growth and dead / diseased wood. See HS1111 and HS14 for more information.
Once harvest concludes, it is usually a grower’s natural inclination to immediately prune their muscadine vines. Pruning after harvest in early fall is not, however, best for maintaining plant condition and optimizing next year’s yield, especially if there is an early frost. Early frosts can surprise the plant before sugars have been moved to the roots for storage during dormancy. Therefore, waiting to prune in mid-January to mid-March will ensure that the vine has had adequate time to go dormant and acclimate to the winter season. For more information please see this article titled “Tips for Properly Pruning Muscadines”.
Pruning is not necessary for citrus in every case, as it is in many temperate fruits, to have excellent production quality and quantity. Citrus trees perform excellently with minimal pruning. The only pruning necessary for most citrus is removing crossing or rubbing branches while shaping young trees, removing dead wood, and pruning out suckers from the root-stock. Homeowners may choose to prune citrus trees to keep them small, but this will reduce potential yield in a commercial setting, since bigger trees produce more fruit.
Often, maturing Satsuma trees produce long vertical branches. It is tempting to prune these off, since they make the tree look unbalanced. To maximize yield, commercial Satsuma growers allow these branches to weep with the heavy load of fruit until they touch the ground. This allows increased surface area for the tree, since the low areas around the trunk are not bare. Additionally, weeds are suppressed since the low branches shade out weed growth. The ground under the trees remains bare, thus allowing heat from the soil to radiate up during cold weather events. The extra branches around the trunk offer added protection to the bud union as well. If smaller trees are desired for ease of harvest, ‘flying dragon’ root-stock offers dwarfing benefits, so that the mature scion cultivar size will only grow to 8-10 feet tall.
Figs should be pruned after fruit production, which usually occurs in early summer. In the winter it is fine to remove dead or diseased wood, but drastic trimming will reduce yield since fruit is borne at the terminal of the previous year’s growth. For more information, please consult publication HS27.
Blueberries beginning to ripen at Blue Sky Berry Farm. Photo by Molly Jameson.
There is something almost magical about picking vibrantly blue blueberries off a bush and eating them fresh. If you watch the blueberries develop, you see them go from shades of pale green and blush red to dark and puffy and bright blue. When a blueberry is ready – you know it!
Blueberries are one of the few crop plants that are actually native to eastern North America. The most popular types are the rabbiteye blueberry (Vaccinium ashei) and the highbush blueberry (Vaccinium corymbosum). Both can be found in northern Florida and southern Georgia, and the highbush blueberry can be found as far north as southeastern Canada. There are at least eight other Vaccinium wild blueberry species that can be found in the woods and near swamps in Florida. They are usually smaller and don’t taste quite as sweet as the rabbiteye and highbush, but birds rely on them heavily for forage.
If you’ve never experienced a fresh blueberry right off the bush, then you may want to consider either foraging for wild blueberries, growing your own, or scouting out a local u-pick blueberry farm near you.
Mulch blueberries with pine straw. Photo by Molly Jameson.
Let’s first consider the joys of growing your own. Blueberries require an acidic soil pH, between about 4.0 and 5.5. Lucky for most of us in the Panhandle, our soil pH is largely naturally acidic. If you have pine trees growing in your area, you most likely can grow blueberries. And the pine straw makes an excellent blueberry mulch! There are many rabbiteye cultivars that have been specifically developed to grow well in our hot climate – requiring fewer “chilling hours” than their northern counterparts. Check out varieties such as Powderblue, Brightwell, Tifblue, and Climax. Highbush blueberries can also do well in northern Florida, although they tend to flower early, making them susceptible to late freezes. Try highbush varieties such as Bluecrisp, Emerald, and Star. Each has its own advantages and drawbacks, such as fruit cracking and insect susceptibility. Click here to learn more about growing blueberries in Florida.
If you are not already growing blueberries, and you want fresh blueberries, then be sure to check out a local u-pick near you. This year you may have noticed we had a warm winter, which delayed the onset of blueberry dormancy. This means the crop is hitting its peak about two or three weeks later than normal. But don’t delay – blueberry season in north Florida typically declines by the beginning of July, so the season is upon us!
If you are in the east Panhandle, be sure to check out u-pick operations such as Blue Sky Berry Farm, Myrtle Creek Farm, Green Meadows Farm, and Blueberry Springs Farm.
Blue Sky Berry Farm, which is located just three miles south of the courthouse in Monticello, on 1180 Ashville Highway, is entering its second season as a u-pick, and its bushes have really grown! They use organic fertilizer and grow using sustainable farming methods. Blue Sky Berry Farm anticipates being open Saturdays and Sundays from 8 a.m. to 1 p.m. this summer, but anyone interested in picking blueberries should first check the Blue Sky Berry Farm website (http://www.bskyfarm.com), as it is updated regularly during the season.
‘Titan’ blueberries at Blue Sky Berry Farm. Photo by Molly Jameson.
Green Meadows Farm, located at 177 East Bluebird Road in Monticello, is five acres of USDA certified organic blueberries. The farm is located among the trees and has been designated a Certified Wildlife Habitat by the National Wildlife Federation. It is open Fridays and Saturdays from 7:30 a.m. to noon and 5:00 p.m. to dusk, and Tuesdays from 7:30 a.m. to noon, while the blueberries last.
Myrtle Creek Farm, located at 2184 Tram Road in Monticello, has beautiful blueberry fields that are dappled with shade in the late afternoon and early evening. They currently have u-pick blueberries and blackberries available. They are open during the weekdays and weekends while the blueberries last, but do call ahead (850-997-0533) to check on availability.
Blueberry Springs Farm is located at 383 Wacissa Springs Road in Monticello, and is celebrating their 25th anniversary of harvesting blueberries. They first planted in December of 1991 and had their first harvest in June of 1991. They are open Tuesdays through Sundays 7:00 a.m. to noon and 5:00 p.m. to 7:00 p.m. You can contact Blueberry Springs Farm at (850) 997-1238 for updates, pricing, and directions.
Also check out the Florida Blueberry Growers Association website and the Florida Department of Agriculture and Consumer Services u-pick locator to discover u-picks around the state, including grape and blackberry u-picks.
Whether you are foraging for wild blueberries, picking your own blueberries, or visiting a u-pick, be sure to bring along plenty of water, a hat, close-toed shoes, and sunscreen, as blueberry season can be a very hot and sunny time of year! But once you’ve experienced your first taste of hand-picked Florida blueberries, you will be hooked and coming back for more each and every summer!
Wash-out in blueberry field, young planting. Image Credit Matthew Orwat
Washed out row in young blueberry field. Image Credit: Matthew Orwat
Although the central Florida panhandle has been hit with excessive rainfall this spring, the blueberry yield this year is on track to be above average. Colder winter temperatures coupled with wet spring weather has enhanced the yield potential of properly tended and well established planted blueberries. If you have a few established blueberry plants in your home orchard, the outlook looks bright. If you do not, don’t fret. There are plenty of U-Pick operations and local farmers market vendors that will have berries available June through July, at great prices!
Blueberries do best planted in low pH soil on slightly sloping ground. This prevents the collection of water and resulting root rot in areas with poor drainage. While this situation is ideal for established blueberry plants, this slightly sloping situation can cause issues for newly planted blueberries. Field wash-outs caused by excessive rainfall can wreck newly planted rows, because the pine bark added to the planting trench is less dense than soil.
After all this rain, what should the home gardener do to ensure a productive harvest this summer? Addition of fertilizer will help. Although blueberries usually require low fertilization rates, if leaves show yellowed edges, red spots or general yellowing, fertilizer may have leached out. Application of a few ounces of ammonium or urea based fertilizer around the root zone (24 inch) of established plants may be beneficial. It is a good idea to look for “Blueberry Special” blends or “Camellia & Azalea” fertilizer. To learn more about blueberry fertilization, consult the Blueberry Gardener’s Guide.
A drier May will help blueberries produce their greatest sweetness as they develop. Late May and June rains could cause fruit split, so less rain during this period is desired!
Blueberries developing for harvest, a month away. Image Credit Matthew Orwat
Blueberry bush, full of developing fruit. Image Credit Matthew Orwat
Washed out rows of young blueberries. Note healthy established plants in the background. No washout due to established root system. Image Credit Matthew Orwat
Emergency drainage ditch dug to reduce wash-out damage from field runoff. Image Credit Matthew Orwat