Garden Maintenance for Xeriscape - Aurora, Colorado
GardenMaintenanceforXeriscape City of AuroraWater Conservation
IntroductionThis class explains the tasks involved in maintaining aXeriscape garden. Topics covered include the removal ofweeds and how to care for your soil; removing spentblooms (deadheading) for extended flowering, plantdivision and pruning. Also addressed are bulbtreatment, irrigation, disease, vegetable gardenmaintenance and tool care. At the end of the class thereis a sample maintenance calendar.The following slide defines terms you will come across inthis presentation.
Glossary of Terms Annual: a plant that usually germinates, flowers, and dies in one year or season Branch collar: the swelling where a branch joins the trunk of a tree Cambium: thin layer of generative tissue lying between the bark and the wood of a stem or trunk Damping-off: a disease of seedlings that is caused by fungi often due to overwatering and results in wilting and death Deadhead: removing spent blossoms to promote new blooms Girdling: removing bark and cambium in a ring that can kill by interrupting the circulation of water and nutrients to a woody stem or trunk Perennial: a plant with a lifecycle of three years or more (annuals are one year, biennials are 2 years) Pre-emergent: chemical herbicides that kill seedlings before they emerge above ground Rhizome: a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes (examples are Iris and Ginger)
Common Types of Weed ControlIdentifying a weed as annual or perennial will determine the type of controlused. An annual lifecycle is one season. Do not allow the plant to flower andset seed - no need to remove the root. Perennials come back year after year.They must be removed with the root so they cannot regenerate. Cultural encourages the growth of desirable plants, with irrigation, mulch and planting at optimum densities. Mulching suppresses annual weeds by limiting light that weeds need to germinate and become established. Some, like Bindweed, can spread by cultivation because their horizontal roots get chopped up and then sprout as new plants. Chemical is the use of various herbicides to kill weeds. Roundup and 2,4-D are most popular for spot spraying weeds. The first kills everything green and the second kills all broadleaf plants but not grass. Chemical application is highly regulated, in terms of how much and when to apply, and the affects on humans, animals and groundwater. Read the directions and follow them! Pre-emergent chemicals stop all seeds from germinating and are often in granular form. They are applied in early spring and fall.
A Chemical Alternative: Corn Gluten this herbicide contains natural chemicals that inhibit root formation at the time of germination. The timing of application is very important for this to work. Apply the herbicide before the weeds germinate. It is considered safe, natural, with no toxicity. The EPA has a factsheet, go to the link below: http://www.epa.gov/oppbppd1/biopesticides/ingredients/factsheets/factsheet _100137.htm Mechanical is the oldest control method. Pulling, mowing, chopping and digging with hand tools can control or eradicate weeds. For annuals and perennials, this can be highly effective. Integrated Pest Management means that none of the above weed controls will work 100% of the time so consider all methods and any combination depending on the situation. A key to staying weed free is to keep soil disturbance to a minimum, mulch and reseed with natives or plant shrubs and perennials. Remove weeds when you see them coming up.
Soil Health Soil composition in Aurora may be comprised of sand, silt, clay or some combination of these. Sand has large particles, making it challenging to retain nutrients and hold water. Clay has the opposite effect due to very small particles which slows water movement, preventing good drainage. Amendments, primarily compost, add organic matter, improve nutrient holding capacity and improve air and water flow. If you have problem soil, adding amendment prior to installing a new landscape will help plants establish healthy root systems. Continuous addition of amendment is not necessary for ornamental plants, particularly natives adapted to the level of organic material in our soils. Soil depletion from heavy feeding vegetable plants like corn and tomatoes will need periodic applications of compost to replenish organic matter in the soil.
Soil Health The need for tilling or turning the soil is a matter of opinion. It is not practical in an established ornamental landscape. People often choose to turn the earth in vegetable gardens. However, it is possible that disturbing the soil can harm beneficial insects living in it and also break down the composition and texture of soil created over time. Mulch is highly recommended for its ability to hold moisture in the soil, prevent erosion, give the garden a finished look and prevent or slow the growth of weed seeds. Organic mulch like shredded bark will need to be replaced as it decomposes every couple of years. Stone mulch, like pea gravel needs to be replaced less frequently.
Annuals and perennials can have spent blooms removed for several reasons. During the growing season, many annuals and perennials benefit from having their old blossoms removed. This action prevents the plant from producing seed and encourages another round of blooming. Many plants profit from this, but not all. Experiment in your landscape and you will quickly learn which plants like to be deadheaded throughout the growing season. A helpful guide is the book The Well-Tended Perennial Garden by Tracy DiSabato-Aust (1998). Perennials in the Xeriscape Demonstration garden at the Aurora Municipal Center (AMC) that rebloom with deadheading are Shasta Daisy, Black- Eyed Susan, Catmint, Red Valerian, Garden Sage, May Night Salvia, English Lavender and Blanket Flower. End of season removal of spent blooms is a way to ‘put the garden to bed’. Some people enjoy a clean and tidy look to the garden for the onset of winter. Trimming in fall eliminates most if not all of the need come spring. Winter interest is the reason nothing is deadheaded in autumn at the demonstration garden at AMC. Perennials and ornamental grasses are attractive covered in snow and moving with a breeze. The sound of seed heads in the wind is also of interest. The seeds also feed wildlife when food is not readily available.
Why should ornamental grasses, bulbs and perennials be divided? To keep plants at the right size for your landscape To remove a dead center for plant health To create more plantsWhen should you divide?For grasses and perennials: After cutting back in spring and new growth has appeared Before the heat of summer stresses plant health and chance of survival Grasses are ready for division when there is no growth in the centerFor bulbs: Dig them up after they have bloomed and pull apart. Replant in different locations for more groupings.How should you divide? Remove plant from the ground, being careful to get all the roots up with minimal damage (dividing while in the ground is possible with care). Cut dead center away. Take a sharp blade and cut into sections, replace in ground and water well.
Tree and Woody Shrub Care Stake recently planted trees to prevent wind damage. For trees that are 1-3 years old, wrap trunks from bottom up to 1st branch to prevent sunscald from Thanksgiving to Easter. Mulch base 2-3” thick and 1” away from trunk to prevent boring insects. Water once a month through winter if ground is not frozen. Hardware cloth or chicken wire placed around the base can prevent rabbits and rodents from girdling.Pruning Prune dead limbs out of trees and shrubs or those with heavy disease or insect infestation. Prune large, overgrown shrubs to thin, don’t shear. After blooming, Lilac, Forsythia, etc., and flowering trees form flowers for next year encased in buds at the tips and shearing will reduce or destroy the next year’s bloom. Prune trees to make them structurally sounder and less prone to future storm damage. Narrow ‘V’ crotches are weak. Cuts must be made just outside the branch collar. Do no harm! An excellent guide book is The Pruning of Trees, Shrubs and Conifers by Brown and Kirkman (2nd edition, 2009). Call an arborist for help if needed.
Growing and Maintaining Bulb Health When the earth is a consistent 50 degrees plant spring blooming bulbs; late September through November before the ground freezes is best. There are also bulbs planted in spring for summer bloom like Gladiolas. Because of their tenderness, they may need to be removed and stored over winter. There are also bulbs that bloom in the fall like Colchicum and Fall Crocus. Bulbs well-suited for our climate and growing conditions are Grape Hyacinths, Crocus, Daffodils, Lilies, miniature Iris, species Tulips and Ornamental Onions called Alliums. All of these have the great benefit of naturalizing, which means they slowly spread and make colonies. Unlike large ornamental tulips, they multiply and become showier with time. Remove and store tender bulbs like Cana, Calla, Dahlia and possibly Gladiolas in a cool, dark place with good air circulation to return to the ground in spring. Bulbs can be divided by digging them up after they have bloomed. Pull them apart and replant in different locations for more groupings. Iris (they are rhizomes, not true bulbs) especially benefit from lifting out of the ground, pulling off the old, dead or decayed areas and replanting.
Maintaining your Irrigation System Create an operational watering schedule and include seasonal adjustments. Less water is required in May and September when it is cool and more is needed at the peak of the growing season in July. Set the schedule to irrigate using short cycles which allows water to soak in, avoiding runoff. Routinely check for damaged sprinkler heads, inadequate coverage, clogged nozzles and leaks. Heads should be upright, not angled. Regularly scheduled assessments will help make fixes easier and quicker. Check your system for appropriate pressure by observing if your heads are misting instead of spraying droplets of water. If excessively misting, you can install a pressure reducer, new sprinklers can be installed or perhaps the pressure can be reduced at the valve. Adjust sprinkler heads as needed to avoid overspray. End of season blow out is important to ensure your system doesn’t crack or break from water trapped in the pipes during the freeze/thaw cycle.
Preventative Measures to Avoid Plant Disease Plant diseases may be caused by several pathogenic organisms, such as fungi, bacteria, viruses and nematodes. In addition, nonliving factors, such as deficiencies or excesses of water, light, temperature, air pollution, pesticides and nutrients, can either predispose a plant to disease or directly cause plant injury. Always choose varieties of plants that are adapted to Colorado growing conditions. Remove infected plant parts immediately. Always disinfect machinery and other tools with steam, hot water under pressure, or a 10 percent solution of household bleach diluted with water. Avoid planting the same crop in the same area of a vegetable garden year after year.
Preventative Measures to Avoid Plant Disease Continued Make sure plants are spaced properly. Air movement decreases when plants are grown too close together and this encourages mildew. Control of most plant diseases can be accomplished without pesticides. Use sound cultural practices, sanitation and well-adapted plant varieties to reduce disease problems. It is important to realize that you must accept some disease loss. Dont expect a perfect garden. For more information go to CSU Cooperative Extension www.ext.colostate.edu/pubs/pubs.html
Vegetable Garden Maintenance In early spring, remove all weeds and add compost to area if necessary. Plant seeds according to packet directions and plant vegetable starts after danger of frost, usually after Mother’s Day in early May. Walls of Water, cold frames and other coverings may be used to plant earlier in the season. At the end of the growing season, before the frost, gather all warm season edibles or place a sheet (not plastic) to cover at night for frost protection. Store gathered vegetables in a cool dark location and most will ripen in 1-2 weeks. Store tomatoes in a cardboard box or heavy paper shopping bag with newspaper layers. Check often for ripening. Make sure to leave a small part of the stem attached. Removing the stem invites rot. Remove plant material from garden bed to prevent disease carry over. Enjoy cold season crops like kale and collard greens. Add a layer of compost over the vegetable garden area after the growing season (this is called top dressing). What does not break down and mix in over the winter can be gently worked in come spring.
Tool Care Remove soil clinging to surface of tools. Cutting edges of trowels, hoes, shovels and similar tools should be sharpened with a file, whetstone or wheel. You can also hire a professional to clean and sharpen hand tools and clean and maintain power tools. After cleaning and sharpening, wipe metal parts with an oily rag to help protect surfaces from dust and rust. Check wooden handles for smoothness and sand if necessary to avoid splinters. Check nuts, bolts and screws and be sure they are tight. When tools are stored in a garage, if possible, keep them off the floor, on a rack or hanging on a wall. This will prevent snow and salt brought into the garage from damaging tools.
Sample Maintenance PlanJanuary Order seeds from catalogues and plan your garden design.February Start cool season vegetable seeds and flowers indoors. If there are warm days, water trees and large woody shrubs and prune limbs.March Start cool season vegetable seeds and flowers indoors. If there are warm days, water trees and large woody shrubs and prune limbs. Check and sharpen garden tools.April Ornamental grasses should be cut back to within 6-12 inches of the ground for spring growth. Divide perennials and replant . Prune Forsythia and Lilac after bloom.May Turn on and test all irrigation. Repair any broken parts and program clock for season. Water plant material slowly and deeply. Weed and apply mulch as needed. Plant vegetable starts. Plant summer blooming bulbs like Dahlias, Lilies and Cana.June Remove spent spring bulb flowers but leave green leaves up until yellow. Plant vegetables like corn and beans to stagger harvest and side dress with compost.July Check irrigation system (this should be done all season long) for problems and alter clock schedule for peak heat of season. Remove weeds before they go to seed.August Plant cool season vegetable crops for late fall harvest. Stay on top of weeds.September Deadhead all spent blooms on perennials if a clean, finished look is desired for winter.October Plant spring blooming bulbs. Harvest remaining vegetables and put in cold storage to ripen. Blow out and turn off irrigation system for the season. Repair any fixes.November Wrap trunk of new, young trees to protect from freeze/thaw of winter sun and remove wrap in April. Mulch as needed. Cut back ornamental grasses if desired for winter.
ConclusionThank you for going through the Xeriscape Maintenance Class.Please visit the six acre Xeriscape Demonstration Garden on the east sideof the Aurora Municipal Center. It is free and open year-round.Water Conservation staff offer classes out of doors during the growingseason. Please check our website for a class schedule and WaterConservation programs at www.aurorawater.org
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