Garden Maintenance for Xeriscape - Aurora, Colorado

1. Garden
Maintenance
for
Xeriscape
City of Aurora
Water Conservation

2. Introduction
This class explains the tasks involved in maintaining a
Xeriscape garden. Topics covered include the removal of
weeds and how to care for your soil; removing spent
blooms (deadheading) for extended flowering, plant
division and pruning. Also addressed are bulb
treatment, irrigation, disease, vegetable garden
maintenance and tool care. At the end of the class there
is a sample maintenance calendar.
The following slide defines terms you will come across in
this presentation.

3. 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)

4. Weeds

5. Common Types of Weed Control
Identifying a weed as annual or perennial will determine the type of control
used. An annual lifecycle is one season. Do not allow the plant to flower and
set 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.

6.  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.

7. Soil Care and Mulch

8. 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.

9. 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.

10. Deadhead

11. 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.

12. Plant Division

13. 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 plants
When 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 center
For 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.

14. Pruning

15. 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.

16. Bulbs

17. 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.

18. Irrigation

19. 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.

20. Disease

21. 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.

22. 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. Don't expect a perfect garden.
 For more information go to CSU Cooperative Extension
www.ext.colostate.edu/pubs/pubs.html

23. Vegetable Garden

24. 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.

25. Tool Care

26. 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.

27. Sample Maintenance Plan
January 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.

28. Conclusion
Thank you for going through the Xeriscape Maintenance Class.
Please visit the six acre Xeriscape Demonstration Garden on the east side
of the Aurora Municipal Center. It is free and open year-round.
Water Conservation staff offer classes out of doors during the growing
season. Please check our website for a class schedule and Water
Conservation programs at www.aurorawater.org