This short-lived perennial, often treated as an annual in colder climates, is grown primarily for it’s pretty, tubular, two-lipped flowers (all colors but blue and yellow). The leaves are narrow and lance shaped (up to 4 inches long). Penstemons like dry but rich soil. They are summer bloomers, attract hummingbirds, and will keep your garden exciting after the spring colors have faded away. Penstemon cardwellii is a spreading, occasionally stem-rooting, evergreen subshrub. Produces in early summer, few-flowered, raceme-like panicles of slender, tubular, funnel-shaped, deep purple flowers. Grows 4 to 8 inches tall, 12 inches wide.
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Size: Height: 0.83 ft. to 1 ft.
Width: 0.33 ft. to 0.67 ft.
Plant Category: perennials,
Plant Characteristics: spreading,
Foliage Characteristics: small leaves, semi-evergreen,
Flower Characteristics: showy, single, unusual,
Flower Color: purples,
Tolerances: deer, drought, heat & humidity,
Bloomtime Range: Early Summer to Early Summer
USDA Hardiness Zone: 6 to 9
AHS Heat Zone: 1 to 9
Light Range: Part Shade to Full Sun
pH Range: 5 to 7.5
Soil Range: Some Sand to Some Clay
Water Range: Dry to Normal
FertilizingHow-to : Fertilization for Young Plants
Young plants need extra phosphorus to encourage good root development. Look for a fertilizer that has phosphorus, P, in it(the second number on the bag.) Apply recommended amount for plant per label directions in the soil at time of planting or at least during the first growing season.
How-to : 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.
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.
LightConditions : Part Sun
Part Sun refers to filtered light, with most sun being received during the afternoon hours. Shade usually occurs during the morning hours.
Conditions : Sun
Sun is defined as the continuous, direct, exposure to 6 hours (or more) of sunlight per day.
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 : 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 : 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 : 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.
Conditions : Full Sun
Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.
WateringTools : Watering Aides
No gardener depends 100% on natural rainfall. Even the most water conscious garden appreciates the proper hose, watering can or wand.
- Watering Cans: Whether you choose plastic of galvanized makes no difference, but do look for generous capacity and a design that is balanced when filled with water. A 2 gallon can (which holds 18 lbs. of water) is preferred by most gardeners and is best suited for outdoor use. Indoor cans should be relatively smaller with narrower spouts and roses (the filter head).
- Watering Hose: When purchasing a hose, look for one that is double-walled, as it will resist kinking. Quick coupler links are nice to have on ends of hoses to make altering length fast. To extend the life of your hose, keep it wound around a reel and stored in a shady area. Prior to winter freezes, drain hose.
- Sprayers: Are commonly thought of as devices for applying chemicals, but can really be a step saver for watering houseplants or small pots of annuals rather that dragging out a hose or making numerous trips with a watering can. The backpack sprayer is best suited for this. Take care not to use any kind of chemical in tanks used for watering!
- Sprinklers: Attached to the ends of garden hoses, these act as an economical irrigation system. Standing Spike Sprinklers are usually intended for lawns and deliver water in a circular pattern. Rotating Sprinklers deliver a circle of water and are perfect for lawns, shrubs and flower beds. Pulse-jet sprinklers cover large areas of ground in a pulsating, circular pattern. The head usually sits up on a tall stem, except for when watering lawns. Oscillating sprinklers are best for watering at ground level in a rectangular pattern.
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 : Water Conditions
When selecting Water Conditions, take into account the amount of water this particular area of your site receives naturally. If you have an irrigation system, select the default normal. Some sites may be naturally wet due to boggy areas by down spots or very dry due to a high sand content. By working with your site's natural conditions, you will reduce maintenance. Do note that even the most drought tolerant plant must first become established, so be willing to provide about 1 inch of water per week during the first year or two.
Conditions : Dry Plants
Dry plants do not tolerate water logged soils and require very little water. Many cacti and succulents fall into this group. Water only when soil becomes completely dry. When watering, do so slowly for a long period of time so that topsoil does not wash away and so that soil has ample time to become moist enough to accept water. It is much better to water for a long time and less frequently allowing soil to dry out completely between waterings.
Conditions : Regular Moisture for Outdoor Plants
Water when normal rainfall does not provide the preferred 1 inch of moisture most plants prefer. Average water is needed during the growing season, but take care not to overwater. The first two years after a plant is installed, regular watering is important. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
Conditions : Outdoor Watering
Plants are almost completely made up of water so it is important to supply them with adequate water to maintain good plant health. Not enough water and roots will wither and the plant will wilt and die. Too much water applied too frequently deprives roots of oxygen leading to plant diseases such as root and stem rots. The type of plant, plant age, light level, soil type and container size all will impact when a plant needs to be watered. Follow these tips to ensure successful watering:
* The key to watering is water deeply and less frequently. When watering, water well, i.e. provide enough water to thoroughly saturate the root ball. With in-ground plants, this means thoroughly soaking the soil until water has penetrated to a depth of 6 to 7 inches (1' being better). With container grown plants, apply enough water to allow water to flow through the drainage holes.
* Try to water plants early in the day or later in the afternoon to conserve water and cut down on plant stress. Do water early enough so that water has had a chance to dry from plant leaves prior to night fall. This is paramount if you have had fungus problems.
* Don't wait to water until plants wilt. Although some plants will recover from this, all plants will die if they wilt too much (when they reach the permanent wilting point).
* Consider water conservation methods such as drip irrigation, mulching, and xeriscaping. Drip systems which slowly drip moisture directly on the root system can be purchased at your local home and garden center. Mulches can significantly cool the root zone and conserve moisture.
* Consider adding water-saving gels to the root zone which will hold a reserve of water for the plant. These can make a world of difference especially under stressful conditions. Be certain to follow label directions for their use.
Conditions : Normal Watering for Outdoor Plants
Normal watering means that soil should be kept evenly moist and watered regularly, as conditions require. Most plants like 1 inch of water a week during the growing season, but take care not to over water. The first two years after a plant is installed, regular watering is important for establishment. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.
How-to : Reduce Watering
This plant requires less watering during winter months, so reduce watering from late November through early March.
PlantingHow-to : Preparing Garden Beds
Use a soil testing kit to determine the acidity or alkalinity of the soil before beginning any garden bed preparation. This will help you determine which plants are best suited for your site. Check soil drainage and correct drainage where standing water remains. Clear weeds and debris from planting areas and continue to remove weeds as soon as they come up.
A week to 10 days before planting, add 2 to 4 inches of aged manure or compost and work into the planting site to improve fertility and increase water retention and drainage. If soil composition is weak, a layer of topsoil should be considered as well. No matter if your soil is sand or clay, it can be improved by adding the same thing: organic matter. The more, the better; work deep into the soil. Prepare beds to an 18 inch deep for perennials. This will seem like a tremendous amount of work now, but will greatly pay off later. Besides, this is not something that is easily done later, once plants have been established.
How-to : Pinching and Thinning Perennials
Once you plant a perennial, it does not mean that you will enjoy years of maintenance-free gardening. Perennials need to be cared for just like any other plant. One thing that distinguishes perennials is that they tend to be active growers that have to be thinned out occasionally or they will loose vigor.
As perennials establish, it is important to prune them back and thin them out occasionally. This will prevent them from completely taking over an area to the exclusion of other plants, and also will increase air circulation thereby reducing the incidence of diseases like botrytis and powdery mildew.
Many species also flower abundantly and produce ample seed. As blooms fade it is advisable to deadhead your plant; that is, to remove spent flowers before they form seed. This will prevent your plants from seeding all over the garden and will conserve the considerable energy it takes the plant to produce seed.
As perennials mature, they may form a dense root mass that eventually leads to a less vigorous plant. It is advisable to occasionally thin out a stand of such perennials. By dividing the root system, you can make new plants to plant in another area of the garden or give away. Also root pruning will stimulate new growth and rejuvenate the plant. Most perennials may be successfully divided in either spring or fall. Do a little homework; some perennials do have a preference.
How-to : Planting Perennials
Determine appropriate perennials for your garden by considering sun and shade through the day, exposure, water requirements, climate, soil makeup, seasonal color desired, and position of other garden plants and trees.
The best times to plant are spring and fall, when soil is workable and out of danger of frost. Fall plantings have the advantage that roots can develop and not have to compete with developing top growth as in the spring. Spring is more desirable for perennials that dislike wet conditions or for colder areas, allowing full establishment before first winter. Planting in summer or winter is not advisable for most plants, unless planting a more established sized plant.
To plant container-grown plants: Prepare planting holes with appropriate depth and space between. Water the plant thoroughly and let the excess water drain before carefully removing from the container. Carefully loosen the root ball and place the plant in the hole, working soil around the roots as you fill. If the plant is extremely root bound, separate roots with fingers. A few slits made with a pocket knife are okay, but should be kept to a minimum. Continue filling in soil and water thoroughly, protecting from direct sun until stable.
To plant bare-root plants: Plant as soon as possible after purchase. Prepare suitable planting holes, spread roots and work soil among roots as you fill in. Water well and protect from direct sun until stable.
To plant seedlings: A number of perennials produce self-sown seedlings that can be transplanted. You may also start your own seedling bed for transplanting. Prepare suitable planting holes, spacing appropriately for plant development. Gently lift the seedling and as much surrounding soil as possible with your garden trowel, and replant it immediately, firming soil with fingertips and water well. Shade from direct sun and water regularly until stable.
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 : 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.
Diseases : Southern Blight
Plants with Southern blight have lesions on the stem at, or near, the soil line. These lesions develop rapidly, girdling the stem and resulting in a sudden and permanent wilting of the plant. High temperatures (above 85 degrees F, 29 degrees C) favor the disease. The fungus attacks a wide range of plants and survives for long periods in soil. To control, treat with a recommended fungicide according to label directions.
MiscellaneousConditions : Deer Tolerant
There are no plants that are 100% deer resistant, but many that are deer tolerant. There are plants that deer prefer over others. You will find that what deer will or will not eat varies in different parts of the country. A lot of it has to do with how hungry they are. Most deer will sample everything at least once, decide if they like it or not and return if favorable. A fence is the good deer barrier. You may go for a really tall one (7 to 8 feet), or try 2 parallel fences, (4 to 5 feet apart). Use a wire mesh fence rather than board, since deer are capable of wiggling through a 12 inch space.
How-to : Cut Flowers
Flowers suitable for cutting maintain their form for several days when properly conditioned and placed in water or soaked oasis. A cut flower should have a fairly strong, long stem, making it easy to work with in arrangements. There are many short stem flowers that make good cut flowers too, but they look best when floated in a bowl or clustered and placed in a juice glass size vase.
For best results, always cut flowers early in the morning, preferably before dew has had a chance to dry. Always make cuts with a sharp knife or pruners and plunge flowers or foliage into a bucket of water. Store in a cool place until you are ready to work with them, this will keep flowers from opening. Always re-cut stems and change water frequently. Washing vases or containers to rid of existing bacteria helps increase their life, as well.
Glossary : Bird Attracting
The term bird attracting applies to any plant that has flowers, fruit, nuts, or structure that attracts birds. Most plants on ""bird attracting"" lists have favorable fruits or flowers that serve as food, but the trunks, limbs and foliage cover that trees and shrubs provide should not be overlooked as they add shelter for raising young and protection from foul weather.
Glossary : Low Maintenance
Low maintenance does not mean no maintenance. It does mean that once a plant is established, very little needs to be done in the way of water, fertilizing, pruning, or treatment in order for the plant to remain healthy and attractive. A well-designed garden, which takes your lifestyle into consideration, can greatly reduce maintenance.
Glossary : Naturalizing
Naturalizing refers to planting in a random pattern, much as itwould occur in nature. If you spend any time in the woods, you've probably noticed that plants often grow in groups. The center of the group is dense and towards the edges, plants are located farther apart. Narcissus bulbs are easy to naturalize if you use this method: fill a bucket with bulbs and toss them out. Plant them where they fall. You will notice a portion of the bulbs are close together while the others have scattered farther away.
Glossary : Rock Garden
A rock garden is a garden that mimics an alpine area, having dwarf conifers, low-growing sub-shrubs, perennials and ground cover. Often, the soil itself tends to be gravelly or rocky.
Glossary : Western
Western refers to plants native to parts of, or all of, the western regions of the United States which border the Pacific Ocean, including California, Oregon and Washington.
Glossary : Western Mountain
Western Mountain refers to plants native to parts of, or all of the Rocky Mountain area, including northern New Mexico, western Texas, western Kansas, western Nebraska, Utah, Colorado, Idaho, Wyoming, Montana, North Dakota, South Dakota, eastern Oregon, eastern Washington, southwestern Canada.
Glossary : Some Sand
Some Sand refers to a soil that drains fast, but has lower water holding capacity due to the presence of a little organic matter. A good workable soil that needs added fertilizer due to lower fertility levels and adequate water. Usually gray in color. Forms a loose, crumbly ball that easily falls apart when squeezed in the hand.
Glossary : Some Clay
Some Clay refers to a soil that is loam-like, but heavier. Drainage is not bad, prolonged periods of rain cause bog-like conditions. Rich in nutrients, but needs the addition of organic matter to improve texture. Easily forms a ball when squeezed and requires a firm tap with finger to crumble. Light brown to slightly orange color.
Glossary : Perennial
Perennial: traditionally a non-woody plant that lives for two or more growing seasons.
Glossary : Semi-Evergreen
Semi-Evergreen: a plant that retains some or most of its foliage throughout the year.
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 : 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 : U. S. Natives
Native plants require lower maintenance and usually have less pest problems. They are key components in the xeriphytic landscape and backyard wildlife habitat. Select your region and the search will look for all plants in the database that are native to your area.
Glossary : Soil Types
A soil type is defined by granule size, drainage, and amount of organic material in the soil. The three main soil types are sand, loam and clay. Sand has the largest particle size, no organic matter, little to no fertility, and drains rapidly. Clay, at the opposite end of the spectrum, has the smallest particle size, can be rich in organic matter, fertility and moisture, but is often unworkable because particles are held together too tightly, resulting in poor drainage when wet, or is brick-like when dry. The optimum soil type is loam, which is the happy median between sand and clay: It is high in organic matter, nutrient-rich, and has the perfect water holding capacity.
You will often hear loam referred to as a sandy loam (having more sand, yet still plenty of organic matter) or a clay loam (heavier on the clay, yet workable with good drainage.) The addition of organic matter to either sand or clay will result in a loamy soil. Still not sure if your soil is a sand, clay, or loam? Try this simple test. Squeeze a handfull of slightly moist, not wet, soil in your hand. If it forms a tight ball and does not fall apart when gently tapped with a finger, your soil is more than likely clay. If soil does not form a ball or crumbles before it is tapped, it is sand to very sandy loam. If soil forms a ball, then crumbles readily when lightly tapped, it's a loam. Several quick, light taps could mean a clay loam.
How-to : Getting the Most Out of Cut Flowers
Cut flowers bring the garden into your home. While some cut flowers have a long vase life, most are highly perishable. How cut flowers are treated when you first bring them home can significantly increase how long they last.
The most important thing to consider is getting sufficient water taken up into the cut stem. Insufficient water can result in wilting and short-lived flowers. Bent neck of roses, where the flower head droops, is the result of poor water uptake. To maximize water uptake, first re-cut the stems at an angle so that the vascular system (the ""plumbing"" of the stem) is clear. Next immerse the cut stems in warm water.
Remember when the flower is cut, it is cut off from its food supply. Once water is taken care of, food is the resource that will run out next. The plants stems naturally feed the flowers with sugars. If you add a bit of sugar (1 tsp.) to the vase water, this will help feed the flower stems and extend their vase life.
Bacteria will build up in vase water and eventually clog up the stem so the flower cannot take up water. To prevent this, change the vase water frequently and make a new cut in the stems every few days.
Floral preservatives, available from florists, contain sugars, acids and bacteriacides that can extend cut flower life. These come in small packets and are generally available where cut flowers are sold. If used properly, these can extend the vase life of some cut flowers 2 to 3 times when compared with just plain water in the vase.
Glossary : Tolerant
Tolerant refers to a plant's ability to tolerate exposure to an external condition(s). It does not mean that the plant thrives or prefers this situation, but is able to adapt and continue its life cycle.
Glossary : Drought Tolerant
Very few plants, except for those naturally found in desert situations, can tolerate arid soils, but there are plants that seem to be more drought tolerant than others. Plants that are drought tolerant still require moisture, so don't think that they can go for extended period without any water. Drought tolerant plants are often deep rooted, have waxy or thick leaves that conserve water, or leaf structures that close to minimize transpiration. All plants in droughty situations benefit from an occasional deep watering and a 2-3 inch thick layer of mulch. Drought tolerant plants are the backbone of xeriphytic landscaping.
Glossary : Fertilize
Fertilize just before new growth begins with a complete fertilizer.