Greene Gardens

Garden Design and Maintenance for Denver

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Winter Watering Guidelines

With below normal precipitation for the month of January, and warm temperatures through the middle of February, it’s a good idea to give your trees and shrubs a drink.  Many areas are suffering from sparse snow cover, low soil moisture and low humidity.  Conditions like these can weaken or damage plant root systems.  Evergreens, south and west-facing lawns, plants near south and west-facing walls and newly installed plants are most susceptible to dry winter conditions.

To give your trees and shrubs a good start on the new growing season, use these guidelines:

  1. Water when air temps are above 40 F.
  2. Use a soil needle, deep root fork, sprinkler, or spray wand
  3. Apply water to many locations around the dripline
  4. Insert the fork or needle no deeper than 8″
  5. Apply 10 gallons of water per inch of tree trunk diameter measured at knee-height.
  6. Apply 5 gallons of water twice a month to newly planted shrubs
  7. Small established shrubs need 5 gallons per month
  8. Large shrubs (over 6 feet) need 18 gallons of water per month.

Your garden will thank you with a hydrated, healthy start to the season!

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Ornamental grass

One spring garden chore in the perennial bed includes trimming, or cutting back ornamental grass. One quick and easy way to do this without causing a lot of additional mess is by using a bungee cord to contain the plumes. Wrap the base of the grass plumes tightly with the bungee cord. Using hedge trimmers, or hand-held pruners, snip the grass plumes 4 or so inches above the ground, and below the bungee cord. Make a level cut.

Hedge trimmers tend to work better on the larger, older clumps of grass and the thicker-bladed varieties like Miscanthus, or Pampas (Erianthus). Newer, smaller clumps of the thinner-bladed varieties, like the feather reed grasses (calamagrostis), and the fountain grasses (pennisetum) can be trimmed with the hand-held pruners.

Lift the dead plumes off the grass plant with the bungee still wrapped around the bunch, and deposit them into the compost pile. Scratch out, or remove, any dead or decayed stems that remain in the center of the grass. Depending on the age of the clump, a dollop of compost in the center can stimulate new growth in that area. Over time, as the center of the grass dies out, the clump can be divided and shared with neighbors.

Your ornamental grass is now ready for new spring growth!

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Dividing Iris

Every 3 or 4 years, one of the fall chores to be completed in the garden is dividing overgrown iris. Likely candidates include those clumps that have stopped blooming, or have become unsightly, or have simply spread beyond their designated bounds.

To divide iris, dig up the crowded clump using a shovel or garden spade. Gently separate the individual rhizomes by hand, or by using a fork or hand spade. Discard shriveled, hollow, lightweight, or rotten rhizomes, and keep the firm rhizomes with good root fibers and one or two leaf fans attached. Replant the individual rhizomes about 12 inches apart. Plant them shallowly, with root fibers facing down, and splayed apart, with a bit of the top surface of the rhizome visible in the planting hole. If planting in a new area, prepare the bed with soil that drains well.

It’s a good idea to clip the top growth 4 or so inches above the root, so that the individual plants don’t become top heavy, and pull out or tip over during the root re-establishment phase. Cutting back the foliage encourages the plant to send energy to the root system, and discourages overwintering pests and disease.

Water well at planting time, but do not overwater. Rhizomes, like bulbs, are easily susceptible to rot, if the soil is too wet.

Share any extras with neighbors, and friends. Dividing iris is a cost-effective way to spread beauty throughout your garden!

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Regular water conservation: the new normal

IMAG0816Recently, I was energized to have a conversation with Kristen Fefes, Executive Director of the Associated Landscape Contractors of Colorado (ALCC). The ALCC is the industry trade organization for landscape contractors, who become members of the organization by agreeing to a code of conduct with respect to Best Management Practices. These BMPs relate to commercial and residential landscape installation and maintenance care throughout Colorado.

This year, the number one topic on the industry plate was the watering restrictions imposed by our recent drought. How, as an industry, do we serve our customers as well as make money for our businesses, and families when our fortunes are so dependent on weather issues?

In my comments with Kristen, I advocated that the water utilities, such as Denver Water, and others, take a longer term view of the problem of landscape water scarcity, and regularly (annually) encourage homeowner and landscape conservation efforts through educational and public awareness events.

Teaching homeowners to conserve landscape water as much as possible in any give year, helps the entire community move to a new paradigm. Rather than take draconian measures in one year, and create the wrong emphasis on the problem (I am using less water, and I get to pay more for the privilege!!!??), I would suggest that through regular water conservation practices, we treat each year as an opportunity to find new water savings in our landscapes. While it might take 10 years or so to convert homeowners and their HOAs to a new look, I would advocate that this is the right approach for the long term health of our communities amidst certain future water scarcity issues.

Certainly those who work in the landscape industry have the knowlege to share different water-saving practices with their clients.

Here’s a suggested survey: Look at what outdoor activities actually take place around your home. Define practical turf zones to accommodate the volleyball net, croquet set-up, or just a place to use the summer slip and slide. Move the swingset to a corner of the lot (within view of Mom’s kitchen window) and place the structure on a non-irrigated (and more forgiving) mulch bed. Use hardscape near the backdoor to define an outdoor eating and living area, or deck.

After assessing your individual needs, choose to regularly irrigate only the practical turf areas, and provide less, or no water to those areas in your landscape that don’t require water. Invest in a good irrigation audit. Find, and fix the leaks, address sprinkler coverage issues, (often this just means adjusting, or replacing a head), and be a better outdoor water consumer. Use mulch, and follow other sustainable practices that improve the health of our landscapes.

We (and our plants)struggled through the beginning of the summer on a two-day per week watering schedule. Now that we’ve added a third day to our watering schedules, I’m very impressed with the health of much of our plant material. Even though we have had extended hot weather – another 95 degree day is forecasted for the Front Range – we have learned that deep, infrequent watering works. It is a best practice that we all can embrace.

Let this be a lesson for future summers. It won’t be long before sprinklers are blown out, and the garden put to bed for the winter. Remember the success of this summer,and resist the urge to change your clock next spring.

You’ll be helping your landscape, as well as conserving water!

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A Few Hardy Souls

imageMother Nature hasn’t been kind to the Denver Metro Area recently.  Heavy snows, and late record cold temperatures followed a winter (and summer and fall!) of drought.  It was great to see this display of garden resilience in one of my client’s gardens as I was doing the spring clean-up.  What made the difference here? 

Mulch.  My sustainability tip #1.  Mulch, in many forms can provide the following benefits:  it retains soil moisture, and reduces soil evaporation, reduces weed growth, and reduces soil temperature fluctuations.  The latter can cause heaving of shallowly rooted plants during a freeze/thaw cycle.  3-4″ of mulch is recommended as an organic, sustainable practice of weed control because the depth of mulch helps prevent weed seeds from setting as easily.  Less weed seeds means less likelihood of the need for later chemical control.  During a drought year, with watering restrictions, retaining soil moisture is the most important benefit of mulch.  

Perennial gardens, and other landscape areas look beautiful with a uniform layer of organic mulch.  Sourcing the mulch locally, or using a recycled product from an arborist or tree company is an additional way to promote sustainability.  As perennial gardens mature, and spreading plant material or groundcover plants fill in the bare areas, less mulch is needed.  Vegetable gardeners may choose to use straw, or grass clippings as organic mulches.  With the latter, it’s best to let the grass clippings dry before application to prevent matting.  Grass clippings from lawns treated with herbicides should not be used as mulch. 

When using organic mulch, it’s also a good idea to test for nitrogen deficiency in the soil occasionally.  As organic mulches decompose, surface soil nitrogen is used in the decomposition process.  If a soils test shows the need, nitrogen can be added to those areas where soil deficiencies occur.   

Check back for other sustainable garden maintenance ideas.

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Drip, drip, drip

IMAG1307 editedDenver Water recently announced a Stage 2 drought, which is serious stuff. The snowpack from the two watersheds on which they rely for their supply is at a ten-year low at 59% and 73% of average respectively. In addition to conserving household water use, all consumers will need to do their part in outdoor water conservation in order to prevent an outright ban on outdoor landscape water use.

Mandatory watering restrictions begin April 1, meaning Denver Water customers may only water two days a week and must follow this schedule:

Single-family residential properties with addresses ending in even numbers: Sunday, Thursday
Single-family residential properties with addresses ending in odd numbers: Saturday, Wednesday
All other properties (multi-family, HOAs, commercial, industrial, government): Tuesday, Friday
In addition, customers must follow the standard annual watering rules:

Do not water lawns between 10 a.m. and 6 p.m.
Do not waste water by allowing it to pool in gutters, streets and alleys.
Do not waste water by letting it spray on concrete and asphalt.
Repair leaking sprinkler systems within 10 days.
Do not water while it is raining or during high winds.

Additionally, trees and shrubs may be watered with a hand-held hose or drip irrigation on the assigned watering days. Spray irrigation is only allowed on assigned watering days.

Annuals and vegetables may be watered any day with a hand-held hose or drip irrigation.

Although painful, Denver Water is implementing rules that should encourage homeowners to pay attention to their outdoor water use and address wasteful irrigation techniques. With the restrictions that begin next week, they are encouraging less-wasteful drip irigation and handwatering over spray irrigation.

This season is a great time to get to know your irrigation contractor well. An investment in an updated irrigation system will provide a lasting benefit to the long-term health of your landscape. Check back here for other ideas to protect your landscape under low water conditions. Please check out Denver Water for further information.