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How to grow a Hydrangea

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  • How to grow a Hydrangea

    ( Bigleaf Hydrangea )

    Hydrangeas are a deciduous, rounded shrub that has ovate, toothed green leaves to 8 inches long. Flowers are usually large and in clusters to 8 inches across bloom in summer and early fall. Lacecaps have small fertile flowers in the center of the cluster, surrounded by larger, four-petaled sterile flowers. Hortensias, also known as Mophead Hydrangeas, have clusters made up of only large sterile flowers. Pink or blue flower color is determined by soil pH. White varieties are not affected by soil pH. Hydrangeas do best in moist, well drained, moderatly fertile soil that is rich in humus. Protection from winter winds and extreme cold is best. Cultivars of Hydrangea macrophylla fall into either Lacecaps or Hortensias. Red to pink flowers occur in alkaline soils and blue to purple flowers in acid soils. Hydrangeas can be forced to change flower color, however, this must be done before bloom begins. To make or maintain blue flowers in alkaline soils, treat with aluminum sulfate. To make or keep pink flowers in acid soil, add lime.

    Important Info : Soil pH determines flower color on the macrocephalum species.

    Hydrangeaceae *

    Height: 3 ft. to 10 ft.
    Width: 2 ft. to 12 ft. *

    Plant Category:
    houseplants, landscape, shrubs, *

    Plant Characteristics:
    low maintenance, round, vase-shaped, weeping, *

    Foliage Characteristics:
    medium leaves, deciduous, *

    Foliage Color:
    green, variegated, *

    Flower Characteristics:
    long lasting, old fashioned/heritage, showy, *

    Flower Color:
    blues, creams, greens, pinks, purples, whites, *

    heat & humidity, seashore, *

    Bloomtime Range:
    Mid Summer to Early Fall *

    USDA Hardiness Zone:
    6 to 9 *

    AHS Heat Zone:
    3 to 3 *

    Light Range:
    Shade to Sun *

    pH Range:
    5.5 to 8 *

    Soil Range:
    Some Sand to Clay Loam *

    Water Range:
    Moist to Moist *

    Plant Care

    FertilizingHow-tos : Fertilization for Established Plants

    Established plants can benefit from fertilization. Take a visual inventory of your landscape. Trees need to be fertilized every few years. Shrubs and other plants in the landscape can be fertilized yearly. A soil test can determine existing nutrient levels in the soil. If one or more nutrients is low, a specific instead of an all-purpose fertilizer may be required. Fertilizers that are high in N, nitrogen, will promote green leafy growth. Excess nitrogen in the soil can cause excessive vegetative growth on plants at the expense of flower bud development. It is best to avoid fertilizing late in the growing season. Applications made at that time can force lush, vegetative growth that will not have a chance to harden off before the onset of cold weather.

    LightConditions : Sun

    Sun is defined as the continuous, direct, exposure to 6 hours (or more) of sunlight per day.

    Conditions : Full to Partial Shade

    Full shade means there is little or no light in the growing zone. Shade can be the result of a mature stand of trees or shadows cast by a house or building. Plants that require full shade are usually susceptible to sunburn. Full shade beneath trees may pose additional problems; not only is there no light, but competition for water, nutrients and root space.
    Partial shade means that an area receives filtered light, often through tall branches of an open growing tree. Root competition is usually less. Partial shade can also be achieved by locating a plant beneath an arbor or lathe-like structure. Shadier sides of a building are normally the northern or northeastern sides. These sides also tend to be a little cooler. It is not uncommon for plants that can tolerate full sun or some sun in cooler climates to require some shade in warmer climates due to stress placed on the plant from reduced moisture and excessive heat.

    Conditions : Partial Sun, Partial Shade

    Part sun or part shade plants prefer light that is filtered. Sunlight, though not direct, is important to them. Often morning sun, because it is not as strong as afternoon sun, can be considered part sun or part shade. If you live in an area that does not get much intense sun, such as the Pacific Northwest, a full sun exposure may be fine. In other areas such as Florida, plant in a location where afternoon shade will be received.

    WateringTools : Watering Aides

    No gardener depends 100% on natural rainfall. Even the most water conscious garden appreciates the proper hose, watering can or wand.
    • Conditions : Moist and Well Drained

      Moist and well drained means exactly what it sounds like. Soil is moist without being soggy because the texture of the soil allows excess moisture to drain away. Most plants like about 1 inch of water per week. Amending your soil with compost will help improve texture and water holding or draining capacity. A 3 inch layer of mulch will help to maintain soil moisture and studies have shown that mulched plants grow faster than non-mulched plants.

      PlantingHow-tos : Pruning Flowering Shrubs

      It is necessary to prune your deciduous flowering shrub for two reasons: 1. By removing old, damaged or dead wood, you increase air flow, yielding in less disease. 2. You rejuvenate new growth which increases flower production.
      Pruning deciduous shrubs can be divided into 4 groups: Those that require minimal pruning (take out only dead, diseased, damaged, or crossed branches, can be done in early spring.); spring pruning (encourages vigorous, new growth which produces summer flowers - in other words, flowers appear on new wood); summer pruning after flower (after flowering, cut back shoots, and take out some of the old growth, down to the ground); suckering habit pruning (flowers appear on wood from previous year. Cut back flowered stems by 1/2, to strong growing new shoots and remove 1/2 of the flowered stems a couple of inches from the ground) Always remove dead, damaged or diseased wood first, no matter what type of pruning you are doing.
      Examples: Minimal: Amelanchier, Aronia, Chimonanthus, Clethra, Cornus alternifolia, Daphne, Fothergilla, Hamamelis, Poncirus, Viburnum. Spring: Abelia, Buddleia, Datura, Fuchsia, Hibiscus, Hypericum, Perovskia, Spirea douglasii/japonica, Tamarix. Summer after flower: Buddleia alternifolia, Calycanthus, Chaenomeles, Corylus, Cotoneaster, Deutzia, Forsythia, Magnolia x soulangeana/stellata, Philadelphus, Rhododendron sp., Ribes, Spirea x arguta/prunifolia/thunbergii, Syringa, Weigela. Suckering: Kerria

      How-tos : Planting Shrubs

      Dig a hole twice the size of the root ball and deep enough to plant at the same level the shrub was in the container. If soil is poor, dig hole even wider and fill with a mixture half original soil and half compost or soil amendment.
      Carefully remove shrub from container and gently separate roots. Position in center of hole, best side facing forward. Fill in with original soil or an amended mixture if needed as described above. For larger shrubs, build a water well. Finish by mulching and watering well.
      If the plant is balled-and-burlapped, remove fasteners and fold back the top of natural burlap, tucking it down into hole, after you've positioned shrub. Make sure that all burlap is buried so that it won't wick water away from rootball during hot, dry periods. If synthetic burlap, remove if possible. If not possible, cut away or make slits to allow for roots to develop into the new soil. For larger shrubs, build a water well. Finish by mulching and watering well.
      If shrub is bare-root, look for a discoloration somewhere near the base; this mark is likely where the soil line was. If soil is too sandy or too clayey, add organic matter. This will help with both drainage and water holding capacity. Fill soil, firming just enough to support shrub. Finish by mulching and watering well.

      ProblemsPest : Slugs and Snails

      Slugs and snails favor moist climates and are mollusks, not insects. They can be voracious feeders, eating just about anything that is not woody or highly scented. They may eat holes in leaves, strip entire stems, or completely devour seedlings and tender transplants, leaving behind tell-tale silvery, slimy trails.
      Prevention and control: Keep your garden as clean as possible, eliminating hiding places such as leaf debris, over-turned pots, and tarps. Groundcover in shady places and heavy mulches provide protection from the elements and can be favorite hiding places. In the spring, patrol for and destroy eggs (clusters of small translucent spheres) and adults during dusk and dawn. Set out beer traps from late spring through fall.
      Many chemical controls are available on the market, but can be poisonous and deadly for children and pets; take care when using them - always read the label first!

      Fungi : Rusts

      Most rusts are host specific and overwinter on leaves, stems and spent flower debris. Rust often appears as small, bright orange, yellow, or brown pustules on the underside of leaves. If touched, it will leave a colored spot of spores on the finger. Caused by fungi and spread by splashing water or rain, rust is worse when weather is moist.
      Prevention and Control: Plant resistant varieties and provide maximum air circulation. Clean up all debris, especially around plants that have had a problem. Do not water from overhead and water only during the day so that plants will have enough time to dry before night. Apply a fungicide labeled for rust on your plant.

      Fungi : Powdery Mildew

      Powdery Mildew is usually found on plants that do not have enough air circulation or adequate light. Problems are worse where nights are cool and days are warm and humid. The powdery white or gray fungus is usually found on the upper surface of leaves or fruit. Leaves will often turn yellow or brown, curl up, and drop off. New foliage emerges crinkled and distorted. Fruit will be dwarfed and often drops early.
      Prevention and Control: Plant resistant varieties and space plants properly so they receive adequate light and air circulation. Always water from below, keeping water off the foliage. This is paramount for roses. Go easy on the nitrogen fertilizer. Apply fungicides according to label directions before problem becomes severe and follow directions exactly, not missing any required treatments. Sanitation is a must - clean up and remove all leaves, flowers, or debris in the fall and destroy.

      Fungi : Leaf Spots

      Leaf spots are caused by fungi or bacteria. Brown or black spots and patches may be either ragged or circular, with a water soaked or yellow-edged appearance. Insects, rain, dirty garden tools, or even people can help its spread.
      Prevention and Control: Remove infected leaves when the plant is dry. Leaves that collect around the base of the plant should be raked up and disposed of. Avoid overhead irrigation if possible; water should be directed at soil level. For fungal leaf spots, use a recommended fungicide according to label directions.

      MiscellaneousGlossary : Perennial

      Perennial: traditionally a non-woody plant that lives for two or more growing seasons.

      Glossary : pH

      pH, means the potential of Hydrogen, is the measure of alkalinity or acidity. In horticulture, pH refers to the pH of soil. The scale measures from 0, most acid, to 14, most alkaline. Seven is neutral. Most plants prefer a range between 5.5 and about 6.7, an acid range, but there are plenty of other plants that like soil more alkaline, or above 7. A pH of 7 is where the plant can most easily absorb the most nutrients in the soil. Some plants prefer more or less of certain nutrients, and therefore do better at a certain pH.

      Glossary : Viruses

      Viruses, which are smaller than bacteria, are not living and do not replicate on their own. They must rely on the cellular mechanisms of their hosts to replicate. Because this greatly disrupts the cell's functionality, outward signs of a viral infection result in a plant disease with symptoms such as abnormal or stunted growth, damaged fruit, discolorations or spots.
      Prevention and Control: Keep virus carriers such as aphids, leafhoppers, and thrips under control. These plant feeding insects spread viruses. Viruses can also be introduced by infected pollen or through plant openings (as when pruning). Begin by keeping the pathogen out of your garden. New plants should be checked, as well as tools and existing plants. Use only certified seed that is deemed disease-free. Plant only resistant varieties and create a discouraging environment by rotating crops, not planting closely related plants in the same area every year.

      Glossary : Fertilize

      Fertilize just before new growth begins with a complete fertilizer.

  • #2
    [align=left]I just bought a Hydrangea two days ago and it is gorgeous.** I planted it in a spot that receives full sun/part shade but what kind of fertilizer should I use??* Or should I even use fertilizer now?* Please give me names of something I can use.[/align]
    [align=left]Also, I have impatiens around my bush.* Will the acid fertilizer be okay for my other flowers in the bed.* Is miracle gro good for hydrangeas?[/align]