What is Lethal Yellowing? As the name implies, lethal yellowing is a fatal disease. It is caused by a phytoplasma, which is a microscopic organism a little less sophisticated than a bacteria. Insects called planthoppers carry the phytoplasma from tree to tree. Planthoppers can’t survive at temperatures below freezing, and this prevents the disease from spreading into other parts of the country. Lethal yellowing disease can’t be controlled by killing the insect vector because insecticides often fail to come into contact with these constantly moving, flying insects....

About the Nevada Lettuce Variety Batavian or Summer Crisp lettuces, such as the lettuce ‘Nevada,’ are tolerant of both cool, spring temperatures and warming, summer temps. Nevada lettuce has thick, ruffled leaves with both a satisfying crunch and velvety smoothness. The outer leaves of Nevada can be harvested or allowed to grow into a gorgeous large, open head. An additional benefit of growing Nevada lettuce in gardens is its disease resistance....

Symptoms of Pod Blight in Lima Bean Plants Symptoms of pod blight of lima beans first manifests as irregular, brown eruptions on fallen petioles in mid-season, and on pods and stems close to maturity. These small, raised pustules are called pycnidia and in wet seasons may cover the entire plant. The upper portions of the plant may yellow and die. Seeds that have become infected may look completely normal or will crack, shrivel, and become moldy....

What is a Mailbox Garden? Gardening around a mailbox adds curb appeal and gives your mailperson something nice to view along their route. Your personal taste will dictate if you are creating a Mediterranean, English country, desert, or other themed space. Remember that plants in this location are often near the roadside and will have to contend with exhaust, chemicals, heat that radiates off the curb or sidewalk, and often dry conditions....

What is Vine Charcoal? Vine charcoal is simply charcoal made from vines, often grape vines. You can also make it from other plant materials. Willow switches work well too, as do twigs from many trees. Just be sure the growth isn’t too new. Depending on what you use and how you prepare it, you can end up with charcoal sticks of varying hardness and even warmer or cooler tones of black....

Cactus enthusiasts love growing thumb cacti (Mammillaria matudae). They are diminutive but fit perfectly in dish gardens with other interesting succulents. Young plants are tidy columns but as they age, they tilt beguilingly and may add other stems for fascinating chaos. This native of Mexico is easy to grow and thrives where other plants cannot. What is a Thumb Cactus? The mammillaria thumb cactus is a drought-tolerant, heat-loving succulent. It hails from regions with low fertility and hot temperatures....

Mango Tree Propagation via Grafting Grafting of mango trees, or other trees, is the practice of transferring a piece of mature, bearing tree or scion to a separate seedling called rootstock. The scion becomes the canopy of the tree and the rootstock the lower trunk and root system. Mango tree grafting is the most reliable and economical method of mango propagation. There are several types of mango recommended for use as rootstock; both Kensington and common mango are suitable, and in South Florida, “Turpentine” is the recommended choice....

Maple Tree Bark Diseases and Damage Canker Fungus Maple Tree Bark Disease Several different kinds of fungi will cause cankers on a maple tree. These fungus are the most common maple bark diseases. They all have the same thing in common, which is that they will create lesions (also called cankers) in the bark but these lesions will look different depending on the canker fungus that is affecting the maple bark....

What are Moondials? Before you get too excited about moondials, there’s one thing you have to understand: they don’t work very well. For one thing, the time the moon is in a particular spot in the sky changes by 48 minutes every night! For another, the moon isn’t always up at night, and sometimes even when it is, it’s not bright enough to cast a readable shadow. Basically, using moondials in gardens for reliable timekeeping is wishful thinking....

What is Mountain Mahogany? Hikers and nature lovers that trek or bike in the challenging vertical regions of the western United States probably have seen mountain mahogany. It is an important broadleaf evergreen to semi-deciduous shrub that prefers dry soil conditions and has the ability to fix nitrogen in soil. As a landscape addition, the plant has great potential, especially since mountain mahogany care is minimal and the plant is very forgiving about site and soil....

What is Mountain Mint? Virginia mountain mint (Pycanthemum virgineanum) grows as a native perennial in most parts of North America. They are hardy perennials in U.S. zones 3-7. In the U.S., they range from Maine to North Dakota and south through Missouri to North Carolina. Like mint plants, mountain mint plants produce the telltale square stems with opposing leaves, and all parts of the plant are highly aromatic. Mature plants can top out at 2- to 3-feet (0....

Mandevilla plants need nighttime temperatures of around 60 F. (15 C.) to force blooming. They cannot tolerate cooler temperatures of less than 40 F. (4 C.) and an outright freeze will kill the vine. Northern gardeners who wonder, “Why won’t my mandevilla bloom?” may be in for some serious work to encourage this tropical wonder to brighten their landscape. Why Won’t My Mandevilla Bloom? Mandevilla are heavy bloomers in the right conditions....

When Portulaca Won’t Bloom When a moss rose plant doesn’t bloom, there may be problems with the growing conditions. Although portulaca is an amazingly low-maintenance plant that thrives on neglect, it still has certain requirements for healthy growth. Drainage: Moss roses prefer poor, dry, well-drained soil. If portulaca won’t bloom, it may be because the soil is too rich or too soggy. Although you can add sand or a small amount of compost to the soil, it may be easier to start over in a new location....

Growing Fruit Trees Fruit trees require full sunlight and well-draining soil in order to thrive. If planting more than one tree, be sure to leave adequate space in between for airflow. Young trees should be pruned to help them develop a framework with a strong central leader and reduced vertical growth. When Should Pear Trees Bear Fruit? A tree purchased at a nursery is usually one or two years old. The time that it takes a tree to mature enough to produce fruit depends on the variety of tree....

Symptoms of Oats with Halo Blight Halo blight in oats presents as small, buff-colored, water-soaked lesions. These lesions usually occur just on foliage, but the disease can also infect the leaf sheaths and chaff. As the disease progresses, the lesions expand and coalesce into blotches or streaks with a characteristic pale green or yellow halo surrounding the brown lesion. Halo Bacterial Blight Control Although the disease is not fatal to the overall oat crop, heavy infections do kill off the leaves....

Growing Oleanders in the Garden The first thing you should know if you want to grow an oleander plant in the garden is that you need to avoid growing oleanders in home landscapes where children and pets play. All parts of oleander shrubs are poisonous and the smoke from burning oleander debris is toxic. Ingesting even a small amount of foliage, flowers, or shoots from an oleander plant can be fatal....

Types of Pansies None of us living today knew pansies when they were wild, weedy plants in the 1700s. But even this new century has seen many changes in the types of pansies available in commerce. New pansy plant types include cultivars offering huge blossoms, ruffled petals and vivid colors and color combinations. So instead of using these modest, inexpensive blossoms as edging for more flamboyant flower displays, many gardeners are using fancy pansy varieties as the main dish....

Partridge peas in gardens provide attractive, bluish-green foliage and bright yellow, nectar-rich blooms that attract bees, songbirds, and several species of butterflies. If this snippet of information has piqued your interest, read on to learn more about partridge pea plants. Partridge Pea Information Partridge pea plants reach mature heights of 12 to 26 inches (30.5-91 cm.). Clusters of bright yellow blooms adorn the plant from midsummer to early fall. This drought-tolerant plant is a great groundcover and is often used for erosion control....

Why Do Peach Trees Need Cold? Like all deciduous trees, peach trees lose their leaves in the autumn and become dormant, but it doesn’t stop there. As winter continues, the trees enter a period called rest. It’s a deep dormancy where a short spurt of warm weather won’t be enough to “wake” the tree up. The cold requirement for peach trees is dependent on this period of rest. Why do peaches need cold?...

Pecan Leaf Blotch Info A minor foliage disease, leaf blotch of pecans occurs throughout the pecan growing region. Symptoms of a pecan tree with leaf blotch first appear in June and July, and primarily affect less than healthy trees. Older foliage and weak or frail trees are more susceptible. The first symptoms appear on the underside of mature leaves as small, round green, velvety spots, while on the upper surface of the leaves, pale yellow blotches appear....