In the last couple of weeks, I’ve had multiple questions regarding trees and shrubs that aren’t looking too hot. These types of calls are common this time of year – it has gotten hot and dry, and plants have fully emerged from winter, causing issues that have been hiding under the surface during the dormant season to manifest as crown or branch dieback. While there are a wide variety of things that can cause dieback, in most cases a little detective work can help pinpoint the issue. Let’s look at a few of the most common causes of dieback and some corrective measures that may help restore the plants to health.
The first thing to do when you notice a plant in decline is nothing. Don’t try and oversaturate it with water. Don’t run out and dump a bunch of fertilizer around it. Many times, these panic measures exacerbate the stress the plant is already under. Instead, I encourage you to give us a call at your local UF/IFAS County Extension Office. We can likely help identify the cause of the problem through a site visit to your property or by you sending us diagnostic photos of the plant with a description of what’s been going on with it – the more information you can provide about the plant and the management practices it has experienced, the better (you can email diagnostic images/information to d.leonard@ufl.edu).
The most common cause of tree/shrub dieback that I see arises from improper planting practices. Most landscape plants should be planted at or just above the surrounding soil level, preferably where the topmost root arises from the trunk. To accomplish this, planting holes should be dug slightly shallower than the rootball’s height and about twice as wide. Planting any deeper than that is probably too deep and can cause problems like trunk and root decay, which lead to crown dieback. Unfortunately, once a plant is planted too deep, it cannot be corrected other than digging up and replanting at the proper depth, which may or may not be possible depending on the size of the tree. Another common issue that can arise after planting is girdling roots. This occurs when plants are grown in plastic containers and develop a root system that circles the inner wall of the pot. If not trimmed, the plant’s root system will continue to grow in this manner, eventually encircling the plant’s trunk, cutting off water and nutrient flow, and leading to crown dieback. Fortunately, this condition can be prevented by cutting, removing, or redirecting these roots at planting.
The next most common cause of plant dieback occurs due to soil disturbance by people. It’s easy to forget but the root zone of trees and shrubs can reach out several times farther than the plant is tall and is easily damaged. Disturbances to the root zone from digging or trenching near trees or compaction from prolonged vehicle travel over the area cause damage that might be slow to appear but can lead to plant decline. If you are doing construction or building near a shrub or tree, try to keep digging machinery as far out of the root zone as possible and avoid repeatedly parking or driving vehicles over the root zone area. Like below ground root damage, trunk damage that occurs from injury by string trimmers, mowers, or animal feeding activity can all disrupt the flow of water and nutrients in plants and prove deadly. There is no cure for this type of damage, so employing physical barriers to prevent damage is key.
The last major stress is environmental in nature and is caused by a water imbalance – either too much or not enough. Dry soil conditions during the planting and establishment phases (first several years after planting) should obviously be avoided if possible – keeping the developing rootzone moist and allowing plant roots to establish in their native soil is critical. Too much water can also cause problems for trees planted in poorly drained soil. Excessive moisture leads to root diseases, which ultimately presents as dieback in the canopy. If planting in an area that tends to stay wet, select a species of plant adapted for that sort of site – some species are more tolerant of “wet feet” than others. While many people expect disease and insect damage to be the cause of an unhealthy plant, they’re often not the biggest culprit and, if they occur at all, are generally secondary to one of the above issues.
Spring has begun, and the flowers are making their debut en masse. The daylily is an exceptionally versatile plant that grows in various colors, shapes, and habitats (Hemerocallis spp.). This plant garners its name from a combination of Greek terms meaning “beauty for a day,” given the tapestry a mass planting provides, they live up to that name. These plants tend to bloom repeatedly for 4-7 weeks, though each individual flower only lasts one day. The time of year flowering begins varies by cultivar, but typically, they may be seen beginning in March, with later bloomers starting around mid-May. Add to their beauty that they are also edible, and you have a plant that can’t be beaten.
UF/IFAS Photo: J. Criss
These perennials are widely available as bare-root or potted plants. Both may be planted in Florida year-round, but planning in spring or autumn will increase success. Inspect roots before you plant them, removing any that are circling or damaged. Plant with the crown at ground level, much like a tree, and keep the soil moist until the plant is established. Though drought tolerant with deep roots, you’ll still want to apply mulch to retain moisture. Fertilizers may be added in spring, summer, and fall based on soil testing. Scouting this planting is important, but insects rarely cause lasting damage. They may be propagated vegetatively or via seed. Vegetative propagation will become important as these plants fill in spaces over the years and will need to be thinned.
Uses in the Landscape
Thanks to the hybridization efforts of growers worldwide, daylilies are available in every spectrum of color and a variety of flower shapes. Daylilies are clumping plants with grasslike foliage and flowers on a scape that may reach up to 36 inches tall. They can be striking when planted in groups of 10, included in a mixed border, or used to highlight a specific area of your gardens. Because they are so varied, it is important to carefully consider the design elements of your landscape and the growing conditions of your landscape when selecting varieties. All cultivars will require some sun, so avoid heavily shaded areas.
UF/IFAS Photo: J. Criss
A Note on Color
Your biggest concern when considering daylilies in the garden will be color. When it comes to landscape design, color integration has three main theories. The first revolves around monochromatic flowering. Simply put, except for the green foliage, all flowers in this type of garden will be one color. Certainly, daylilies fall into this category, which are often yellow and may be quite striking. The second theory on color in your garden spaces is an analogous scheme in which 3-5 colors on the color wheel are utilized to create continual flow. In this case, find daylilies with red flowers and pair them with violet or yellow flowers. The final theory on color use in gardens is a complementary scheme. In this instance, colors on opposite sides of the color wheel are utilized. The contrast created by this method can create a striking difference that draws the eye to a specific point. Keep in mind that these are all theories. Ultimately, it is your landscape, and you should use those flower colors which satisfy your sensibilities.
UF/IFAS: Gail Hansen
Daylilies are a wonderful plant for your landscape. Easy to grow with great variety, few others can compete with them. For more information, see this Ask IFAS document. As always, please contact your local extension agent for additional information on this and any topic regarding your gardens and more.
Here in North Florida, it is not uncommon to see a few citrus trees in a residential landscape. With Florida being the second highest producing state of citrus, it is not out of the normal to see them when you are out and about. They are a great option to keep a lush green aesthetic in your yard. But, what other options are there for the homeowner that wants to add some edible diversity to their landscape? In this article we will be discussing a few of the many edible landscape choices that can add both diversity and a sweet treat to your yard.
A popular edible landscape option is the rabbiteye cultivar of blueberry. The rabbiteye blueberry plant is considered easier to grow for the first time blueberry grower in comparison to the southern high bush cultivar. This cultivar thrives in acidic soils and requires a soil pH of 4.0 to 5.5. When planting, the use of pine bark mulch is a great organic method to satisfy the soil pH requirement. Mixing composted pine bark mulch in the soil and adding additional mulch after the bush is planted will add to the soil’s organic matter over time. Mulching also aids the establishment of young plants and moderates soil temperatures and weed control. For variety selection, mid-to-late season rabbiteye cultivars are best for Northwest Florida, as they are more cold tolerant and less susceptible to lose their flowers and young set fruit in late winter/early spring frosts. Common mid-to-late season rabbiteye’s are ‘Vernon’, ‘Brightwell’, ‘Powderblue’, ‘Tifblue’, and ‘Georgia Giant’. Because blueberry plants are not “self-unfruitful”, they will require more than one variety to cross-pollinate with in order to produce fruit. Two is great, but three plants will also encourage larger fruit set for you and your family to enjoy!
Blueberry Set Fruit, Jackson County Master Gardener Demo Garden
Another option that has steadily grown interest in the Florida Panhandle is the apple tree. There are two known cultivars of apple that are acclimated to the North Florida region due to their low chill hour requirement cold tolerance. This is the ‘Anna’ Apple and the ‘Dorsett Golden’ Apple. Apple trees will perform best in full sun locations of the yard and prefer a well-drained soil. The chilling hour requirement for these cultivars of apple are between 400-600 hours. You will begin to see the fruit ripen in the months of May to June. The ‘Anna” Apple has been compared to the well known ‘Red Delicious” that is best known in northern region of the United States. Planting should occur in early spring and planting holes should be big enough that the root system does not become over crowded from limited expansion space. There is no UF/IFAS fertilizer recommendation for the apple tree because it is not commercially produced in Florida, but generally a fertilizer such as 10-10-10 can be used.
‘Anna’ Apple, Photo Credit: UF/IFAS NFREC
The blackberry is a great choice as well for an edible landscape. There are several blackberry species that are native to Florida. Most blackberries produce thorns on their shoots, but many new cultivars have been developed as thornless. When selecting your planting location, low-lying areas should be avoided to deter from over-flooding of your plants. Blackberries thrive best in well-drained soils and high air flow and should be planted between December to February. Pollination of the plant is very important to ensure the quality and quantity of the fruit produced; blackberries range from self-fruitful to self-unfruitful depending on the cultivar. ‘Apache’, ‘Flordagrand’, and ‘Choctaw’ are a few examples of many blackberry cultivars available. The first year after the blackberry has been established, it will only produce new shoots with no berries. These shoots are called primocanes. The second year, berries will produce on these shoots and then be called floricanes. It is important to cut the tip off the primocanes after they have reached about 3 ft in height to encourage the shoot to create lateral branches. Floricanes will die off after they have produced fruit. Trellises can be used as well to encourage the plant to grow upright and off the ground.
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When you think of fruit production in Florida, blackberries (Rubus spp.) will not quickly jump to mind. Many people envision viny plants infiltrating your gardens and attacking you with their tiny spines. These are dewberries and are not known for large or consistent fruit. Though scientifically of the same name, bush varietals are a world apart. Bush blackberries fall into the rosaceae or rose family. They are deciduous fruiting shrubs, generally acclimatized to temperate environments. Luckily for us, they grow in the Panhandle. They’ve not taken off as an agronomic crop large scale due to the brittle nature of their fruit. However, with estimated production rates of 6000lb per acre many parts of the country, their value in home food production is undeniable.
UF/IFAS photo: Brent Sellers
Which to Pick
The University of Florida has been heavily breeding blackberries, but as with all gardens, plant selection is vital. The most critical factor in selecting blackberries is the chill hour requirement. You may recall that chill hours are the total time below 45 degrees a plant needs to set fruit the following spring. The vast majority of our area gets 660-700 chill hours per year on average, with the extreme north end getting upwards of 800 hours yearly. Once this is determined, the focus shifts to growth habit. Many grow erect and will not need trellising, but there are cultivars that vine and will need support. A final consideration for cultivar selection is whether or not they will need pollinator plants as an accompaniment. If the berries you want have this need, pick a compatible cultivar with a similar bloom time. Some cultivars that will do well in north Florida include ‘Arapaho,’ ‘Chickasaw,’ and ‘Choctaw.’
UF/IFAS photo: Mary Salinas
Planting and Care
Plant blackberries over the winter months much as you would any deciduous fruits. If you must store the plant before planting, keep the roots moist if you will be holding the plant for any amount of time. Ensure the first main root is just above the soil line, and remove any air pockets as you backfill the planting hole. Keep the soil moist but not overly wet, and avoid overhead watering. Space the plants according to their full size, which varies based on cultivar. These have shallow root systems and are therefore not heavy feeders. As a result, apply nutrients in the spring of the year they’re planted at ¼ pound per plant. In subsequent years apply ¼ to ½ a pound per plant twice a year. Irrigation and weed control will also be critical in their first year. Irrigation will become less important once the shrubs establish in their location.
Growing food in your home landscape is a great way to reconnect with your property and bring your food system as local as possible. Blackberries are low-maintenance fruit that, once established will provide years of production with minimal effort. For more information, see this Ask IFAS document. Contact your local extension agent for additional information on this and any other topic regarding your gardens.
The oncoming of spring is heralded by several events. Wildflowers bloom, temperature rises, and insects awaken from their wintry slumber. The latter of these is the impetus for this article. I’m sure you have heard the buzzing of the bees already, but there is more to come. Florida is host to 315 species of native bees in addition to honey bees (Apis mellifera) which are a non-native species. Native bees in Florida are separated into six families, fulfilling several niches within our landscape. This article is only focused on a few of these.
The Sweat Bees
The sweat bees fall into the family Halictidae. These vary greatly in appearance and size with the majority being very small. Often metallic black, but may also be seen in shades of green, blue, or purple they are hard to miss in your landscape. Most sweat bees are ground nesting though some can be found above. Wildflowers, stone fruits, and sunflowers are the primary nectar sources for these bees particularly in early spring.
IFAS photo: James R. Weaver, Shiala M. Naranjo, Emily Noordyke, and Rachel E. Mallinger
Bumble Bees
Bumble bees (Bombus spp.) are in the family Apidae. Ground dwelling, the queen overwinters in the soil emerging in early spring to feast on wildflower nectar. Often mistaken as carpenter bees (Xylocopta spp.), they are distinguishable by the hairs covering their bodies which are lacking in carpenter bees. They are one of two bee species seen carrying pollen sacks, honey bees being the other. All but one of the five species in this genera may be found in the Panhandle where they are important pollinators for many native and ornamental plants.
Photo Credit: Tony Wills
Mason Bees
One of our more unique species, Mason bees of family Megachilidae live above ground lining their nests with mud. Solitary by nature, these are prominent pollinators of fruit trees and blueberries. A variety of color makes them difficult to even identify as a bee. They often come in dark blue, black, or white striped. Much like honeybees, some species of mason bees are purchased from online sources specifically for orchards.
IFAS photo: Credit: Tony Wills, en.wikipedia.org
Carpenter Bees
Carpenter bees are the final subject covered here and are split into two subfamilies. Large carpenter bees (Xylocopta spp.) chew their nests into solid wood. That the wood is sometimes fence posts, water tanks or your home means that this insect may be an economic pest. These are large and as mentioned above often mistaken for bumble bees. Small carpenter bees (Ceratina spp.) are differentiated mainly by size as they are much smaller than the large carpenter bee. They may be a variety of colors as well and nest by hollowing out the pith of broken or burnt plant stems. As they make their nests in already broken plant tissue, they are not considered of economic importance.
Large Carpenter Bee IFAS photo: Paul ChoateSmall Carpenter Bee Photo: USGS Bee Inventory and Monitoring Lab
Conclusion
Native bees are an important part of pollination in the Florida Panhandle. It is worthwhile to get to know which species are active in your landscape. Provide habitat and nectar to them, and they will help your plant life bloom. For more information on creating habitat for native pollinators, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
