Dendrobium densiflorum ( Dendrobium Orchid )

Characteristics

Cultivar:	n/a
Family:	Orchidaceae
Size:	Height: 0.83 ft. to 1 ft. Width: 0.83 ft. to 1 ft.
Plant Category:	houseplants, orchids,
Plant Characteristics:	high maintenance,
Foliage Characteristics:	evergreen,
Foliage Color:	green,
Flower Characteristics:	showy,
Flower Color:	yellows,
Tolerances:

Requirements

Bloomtime Range:	Mid Spring to Late Spring
USDA Hardiness Zone:	11 to 11
AHS Heat Zone:	Not defined for this plant
Light Range:	Part Shade to Full Sun
pH Range:	5.5 to 6.5
Soil Range:	Bark to Bark
Water Range:	Dry to Moist

Plant Care

Fertilizing

How-to : Fertilization for Annuals and Perennials

Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.

How-to : Fertilizing Houseplants

Houseplants may be fertilized with: 1. water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; 3. or organic fertilizers such as fish emulsion. Water soluble fertilizers are used every two weeks or per label instructions. Controlled, slow-release fertilizers are carefully worked into the soil usually only once during the growing season or per label directions. For organic fertilizers, such as fish emulsion, follow label directions. Allow houseplants to 'rest' during the winter months; stop fertilizing in late October and resume feeding in late February.

Light

Conditions : Partial Shade

Partial Shade is defined as filtered light found beneath trees with high limbs. Partial shade usually offers some protection from direct afternoon sun.

Conditions : Light Conditions

Unless a site is completely exposed, light conditions will change during the day and even during the year. The northern and eastern sides of a house receive the least amount of light, with the northern exposure being the shadiest. The western and southern sides of a house receive the most light and are considered the hottest exposures due to intense afternoon sun.

You will notice that sun and shade patterns change during the day. The western side of a house may even be shady due to shadows cast by large trees or a structure from an adjacent property. If you have just bought a new home or just beginning to garden in your older home, take time to map sun and shade throughout the day. You will get a more accurate feel for your site's true light conditions.

Conditions : Moderate Light for Houseplants

Place houseplants that require moderate light within 5 feet of an eastern or western exposure window.

Conditions : Full Sun for Houseplants

Don't underestimate the light needs of houseplants that require full sun -- they are often tropicals. Place them within 2 feet of a southern exposure window, or at the very minimum, a room that stays bright. Bright rooms have light colored walls, allowing for light reflection.

Conditions : Moisture-loving Houseplants

Houseplants that require ample water, or those labeled as moisture-loving houseplants require that they be watered thoroughly until the soil is saturated and then drains freely from holes in the bottom of pot. Re-water when potting soil becomes dry to the touch an inch or so below the soil surface.

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.

Conditions : Full to Partial Sun

Full sunlight is needed for many plants to assume their full potential. Many of these plants will do fine with a little less sunlight, although they may not flower as heavily or their foliage as vibrant. Areas on the southern and western sides of buildings usually are the sunniest. The only exception is when houses or buildings are so close together, shadows are cast from neighboring properties. Full sun usually means 6 or more hours of direct unobstructed sunlight on a sunny day. Partial sun receives less than 6 hours of sun, but more than 3 hours. Plants able to take full sun in some climates may only be able to tolerate part sun in other climates. Know the culture of the plant before you buy and plant it!

Conditions : Bright Light for Houseplants

Houseplants requiring bright light should be placed within 2 feet of an eastern or western exposure window or within 2 to 5 feet of a southern exposure window.

Conditions : Light and Plant Selection

For best plant performance, it is desirable to match the correct plant with the available light conditions. Right plant, right place! Plants which do not receive sufficient light may become pale in color, have fewer leaves and a "leggy" stretched-out appearance. Also expect plants to grow slower and have fewer blooms when light is less than desirable. It is possible to provide supplemental lighting for indoor plants with lamps. Plants can also receive too much light. If a shade loving plant is exposed to direct sun, it may wilt and/or cause leaves to be sunburned or otherwise damaged.

Watering

Conditions : Normal

Normal is defined as regular watering to a depth of 18 inches, but periodically dries out in the top 7 inches between waterings.

Conditions : Moist

Moist is defined as soil that receives regular watering to a depth of 18 inch deep, does not dry out, but does not have a drainage problem either.

Conditions : Normal Watering for Houseplants

Houseplants that require normal watering should be watered so that soil is completely saturated and excess water runs out the bottom of the pot. Never water just a little bit; this allows mineral salts to build up in the soil. The key to normal watering is to allow the top inch or two of potting soil to dry out between waterings. Check frequently as certain times of the year may dictate that you water more frequently. Also, some plants that require normal watering during the growing season, may require less during the winter months when they are dormant.

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.

Planting

How-to : Preparing Containers

Containers are excellent when used as an ornamental feature, a planting option when there is little or no soil to plant in, or for plants that require a soil type not found in the garden or when soil drainage in the garden is inferior. If growing more than one plant in a container, make sure that all have similar cultural requirements. Choose a container that is deep and large enough to allow root development and growth as well as proportional balance between the fully developed plant and the container. Plant large containers in the place you intend them to stay. All containers should have drainage holes. A mesh screen, broken clay pot pieces(crock) or a paper coffee filter placed over the hole will keep soil from washing out. The potting soil you select should be an appropriate mix for the plants you have chosen. Quality soils (or soil-less medias) absorb moisture readily and evenly when wet. If water runs off soil upon initial wetting, this is an indicator that your soil may not be as good as you think.

Prior to filling a container with soil, wet potting soil in the bag or place in a tub or wheelbarrow so that it is evenly moist. Fill container about halfway full or to a level that will allow plants, when planted, to be just below the rim of the pot. Rootballs should be level with soil line when project is complete. Water well.

How-to : Potting Indoor Plants

Make sure that the plant you have chosen is suitable for the conditions you are able to provide it: that it will have enough light, space, and a temperature it will like. Remember that the area right next to a window will be colder than the rest of the room.

Indoor plants need to be transplanted into a larger container periodically, or they become pot/root-bound and their growth is retarded. Water the plant well before starting, so the soil will hold the root ball together when you remove it from the pot. If you have trouble getting the plant out of the pot, try running a blade around the edge of the pot, and gently whacking the sides to loosen the soil.

Always use fresh soil when transplanting your indoor plant. Fill around the plant gently with soil, being careful not to pack too tightly -- you want air to be able to get to the roots. After the plant is in the new pot, don't fertilize right away... this will encourage the roots to fill in their new home.

The size pot you choose is important too. Select one that is not more than about 1 inch greater in diameter. Remember, many plants prefer being somewhat pot bound. Always start with a clean pot!

How-to : Repotting Orchids

Potting Terrestrial Orchids Good drainage is important. Mix 3 parts fibrous peat, 3 parts coarse grit, 1 part perlite, and 1 part charcoal. Select a pot that will accommodate roots and about 2 years growth, but no more. Make sure that it has a drainage hole. Hold the orchid over the pot so that the crown is just below the rim of the pot. With your other hand, fill pot with moistened soil mix, tamping to firm. There really is no need to add crockery to the bottom of the pot, but you may want to add a small square of wire mesh or other permiable fabric over hole in bottom of pot. Potting Epiphytic Orchids Epiphytes prefer conditions where roots can be exposed, therefore, tight pots and close-contact soil mixes do not work well and will induce rot. Mix 3 parts dust-free, medium-grade bark, 1 part coarse grit or perlite, 1 part charcoal, and 1 part peat moss together, OR use a commercial orchid mix. As with the terrestrial orchid, select a pot that will accommodate roots and about 2 years growth, but no more. Make sure that it has a drainage hole. Even better, select an orchid pot, which has vertical slits down sides. Hold orchid over pot so that crown is just below the rim of the pot. With other hand, fill pot with moistened bark mix, tamping to firm. Some epiphytes do not need to be potted and prefer to grow on a mound or slab of bark. Until roots attach, tie orchid in place with fishing line. Constant humidity is a must. Support Orchids that have long flower stalks will need staking. Staking is best done as stem grows and before buds open. Many growers prefer to insert stake when potting orchid, but it is up to you.

Problems

Pest : Spider Mites

Spider mites are small, 8 legged, spider-like creatures which thrive in hot, dry conditions (like heated houses). Spider mites feed with piercing mouth parts, which cause plants to appear yellow and stippled. Leaf drop and plant death can occur with heavy infestations. Spider mites can multiply quickly, as a female can lay up to 200 eggs in a life span of 30 days. They also produce a web which can cover infested leaves and flowers.

Prevention and Control: Keep weeds down and remove infested plants. Dry air seems to worsen the problem, so make sure plants are regularly watered, especially those preferring high humidity such as tropicals, citrus, or tomatoes. Always check new plants prior to bringing them home from the garden center or nursery. Take advantage of natural enemies such as ladybug larvae. If a miticide is recommended by your local garden center professional or county Cooperative Extension office, read and follow all label directions. Concentrate your efforts on the undersides of the leaves as that is where spider mites generally live.

Diseases : Bulb Rot

Improperly stored bulbs, or bulbs that are too wet in their dormant stage (usually summer), will be susceptible to fungal diseases that cause them to rot. To prevent this, store bulbs properly when out of the ground. Avoid planting bulbs in poorly drained soils. Fusarium bulb rot can be a serious problem which attacks both the growing plant and stored bulb. Usually introduced by an infected bulb, corm, soil, or even tools, the fungus enters the plant through an abrasion in the tissue. This problem is worse in warm climates where temperatures rarely drop into the freezing range and can persist in soil that stays 60 to 70 degrees Farenheit. Prevention and Control: Buy bulbs that are firm, not mushy. Avoid planting new bulbs in areas where the disease has been present. Unfortunately, there is no treatment for Fusarium bulb rot. Remove all infected bulbs and soil in the immediate area.

Pest : Mealybugs

Small, wingless, dull-white, soft-bodied insects that produce a waxy powdery covering. They have piercing/sucking mouth parts that suck the sap out of plant tissue. Mealybugs often look like small pieces of cotton and they tend to congregate where leaves and stems branch. They attack a wide range of plants. The young tend to move around until they find a suitable feeding spot, then they hang out in colonies and feed. Mealybugs can weaken a plant leading to yellow foliage and leaf drop. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.

Prevention and Control: Isolate infested plants from those that are not. Consult your local garden center professional or the Cooperative Extension office in your county for a legal insecticide/chemical recommendation. Encourage natural enemies such as lady beetles in the garden to help reduce population levels of mealy bugs.

Pest : Whiteflies

Whiteflies are small, winged insects that look like tiny moths, which attack many types of plants. The flying adult stage prefers the underside of leaves to feed and breed. Whiteflies can multiply quickly as a female can lay up to 500 eggs in a life span of 2 months. If a plant is infested with whiteflies, you will see a cloud of fleeing insects when the plant is disturbed. Whiteflies can weaken a plant, eventually leading to plant death if they are not checked. They can transmit many harmful plant viruses. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.

Possible controls: keep weeds down; use screening in windows to keep them out; remove infested plants away from non-infested plants; use a reflective mulch (aluminum foil) under plants (this repels whiteflies); trap with yellow sticky cards, apply labeled pesticides; encourage natural enemies such as parasitic wasps in the garden; and sometimes a good steady shower of water will wash them off the plant.

Pest : Aphids

Aphids are small, soft-bodied, slow-moving insects that suck fluids from plants. Aphids come in many colors, ranging from green to brown to black, and they may have wings. They attack a wide range of plant species causing stunting, deformed leaves and buds. They can transmit harmful plant viruses with their piercing/sucking mouthparts. Aphids, generally, are merely a nuisance, since it takes many of them to cause serious plant damage. However aphids do produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface growth called sooty mold.

Aphids can increase quickly in numbers and each female can produce up to 250 live nymphs in the course of a month without mating. Aphids often appear when the environment changes - spring & fall. They're often massed at the tips of branches feeding on succulent tissue. Aphids are attracted to the color yellow and will often hitchhike on yellow clothing.

Prevention and Control: Keep weeds to an absolute minimum, especially around desirable plants. On edibles, wash off infected area of plant. Lady bugs and lacewings will feed on aphids in the garden. There are various products - organic and inorganic - that can be used to control aphids. Seek the recommendation of a professional and follow all label procedures to a tee.

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.

Miscellaneous

Glossary : Container Plant

A plant that is considered to be a good container plant is one that does not have a tap root, but rather a more confined, fibrous root system. Plants that usually thrive in containers are slow- growing or relatively small in size. Plants are more adaptable than people give them credit for. Even large growing plants can be used in containers when they are very young, transplanted to the ground when older. Many woody ornamentals make wonderful container plants as well as annuals, perennials, vegetables, herbs, and bulbs.

Glossary : Evergreen

Evergreen refers to plants that hold onto their leaves or needles for more than one growing season, shedding them over time. Some plants such as live oaks are evergreen, but commonly shed the majority of their older leaves around the end of January.

Glossary : Plant Characteristics

Plant characteristics define the plant, enabling a search that finds specific types of plants such as bulbs, trees, shrubs, grass, perennials, etc.

Glossary : Flower Characteristics

Flower characteristics can vary greatly and may help you decide on a ""look or feel"" for your garden. If you're looking for fragrance or large, showy flowers, click these boxes and possibilities that fit your cultural conditions will be shown. If you have no preference, leave boxes unchecked to return a greater number of possibilities.

Glossary : Foliage Characteristics

By searching foliage characteristics, you will have the opportunity to look for foliage with distinguishable features such as variegated leaves, aromatic foliage, or unusual texture, color or shape. This field will be most helpful to you if you are looking for accent plants. If you have no preference, leave this field blank to return a larger selection of plants.

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.

Plant Images