Creating Your Colorado-friendly Garden: 2.b - Site Physical Assessment

In this post, we continue to explore the steps required to create a Colorado-friendly garden. In the last post, we discussed how to discover the characteristics of your garden’s soil.  In this post, we consider other physical factors that affect your garden design.  For a list of all the posts in this series see the page ‘Creating Your Colorado-friendly Garden’ (right).

Measuring precipitation in your own yard: good idea

1. Yearly Precipitation

Nothing influences plant growth like the amount and pattern of precipitation. You probably have a basic understanding of precipitation in your area. But as climate changes, and water becomes more scarce (at least in the U.S. Southwest), you need to take a careful look at precipitation patterns over time.

Yearly climate data is readily available on the internet. Local television channels or the Weather Channel have some good information on average temperature and precipitation for your area. If you live in the U.S., NOAA has good climate information – including historical data - at : http://www.ncdc.noaa.gov/new-climate-information. 

Here is this summer's precipitation,

as measured in the garden.

As you know, precipitation can vary widely by geographic area. Consider purchasing an inexpensive rain gauge and tracking precipitation in your own backyard. Check with your neighbors. You may have a helpful neighbor with precipitation records going back years or even decades! These will provide a better indicator of your neighborhood’s precipitation than any other source.

Note the precipitation information, and its source, on your Site Summary Sheet (http://www.slideshare.net/cvadheim/physical-characteristics-of-your-site-summary)

An interesting garden includes both sun and shade

 2. Sun and Shade.

Three main factors influence how well a plant will do in a given location: soil moisture, temperature extremes and the amount of sunlight/shade. We tend to think of Colorado native plants as being ‘sun lovers’, and this is true for most plants in some plant communities (for example, desert communities). But most plant communities include a combination of sun- and shade-loving plants. The shade-lovers will be found growing in the shade of trees and shrubs, in the bottoms of canyons or forests and on north-facing slopes.

There are many degrees of shade – both in nature and in the garden (definitions are given below). The trick is to match the light requirements of the plants to those of the garden. Shade is often viewed as a deterrent to gardening, which is unfortunate. While shady areas do present unique challenges, lovely native plant gardens can be created in lower light environments. In fact, shade gardens have many special attributes and advantages.

• The lower light intensity creates a calm, peaceful atmosphere, a restful place.
• As the hot sun beats down, toasting the ground and wilting everything in sight, a lush green shade garden becomes a paradise, a refuge from the scorching temperatures of a summer day.
• Shady spots are more enjoyable to work in during the heat of the summer.
• Depending on the site and plant selection, these sites may require less watering, as there is less water evaporation.
• In a shady garden the play of light and shade, ever-changing throughout the day and from season to season, adds to the beauty of the garden.  
  

Parts of Mother Nature's Montrose Garden are

 quite shady at 9:00 a.m.

Creating Your Light & Shade Map - Mapping light zones in your garden

To really understand your garden’s patterns of light requires close observation, ideally in winter, spring and summer. Mapping your garden’s light conditions means you'll need to spend some time outside in your yard. Of course, you could break this down into three or four parts over three or four days; on the other hand, this is a great opportunity to really enjoy being outside. Even if you think you know your garden, we guarantee you will be surprised by your results! And once you’ve created a good Light & Shade Map you will find it much easier to select suitable plants.

While you may be tempted to just guess at the light conditions, we highly recommend taking the more methodical approach. Our own experience taught us that while we thought we knew our gardens’ shade, we really didn’t! We found that unless you actually observe the shade patterns, you may forget crucial factors such as the shade cast by walls, umbrellas and other shade-makers; or underestimate the amount of morning sun hitting plants under your trees.

Summer and Fall shade patterns:

Mother Nature's Montrose Garden

Start with a copy of Base Map 2. You will map the shaded areas at 9:00 a.m, noon and 3:00 p.m. Note the date of the shade map since light and shade patterns vary with the season. At 9:00, noon and 3:00, draw a line roughly showing where the sun is touching still (or where the shade begins) in each area of the yard. Note also areas of Deep shade and High/dappled shade (see table below for definitions). At the end of the day you'll be able to construct your final Light and Shade Map, which maps the shade regimens for each area of the garden. See an example, below, of a Shade Map in a small garden, done on August 21^st .

Bear in mind that some factors affecting sunlight patterns will change during the course of the year. So, to really understand the light patterns in your garden you may want to re-map your garden in summer and winter.

Terms commonly used to describe light conditions in the garden

Term	Description	Notes for your garden
Reflected sun with heat	A south facing wall that can break 130 F on a good day, like a south wall in Delta, Grand Junction or Cortez.	This is a pretty tough regimen for most plants.  Only sun-loving plants from desert communities can survive.
Full sun	A reflective wall in the mountains; full sun everywhere else (at least 6 hours/day).	Many plants from local Grasslands, Shrublands, Oak Woodlands, Pinyon-Juniper, and open Forest
Afternoon sun	Can be a challenge in hot gardens.   Often along walls.	Plants that can take heat – shrub & desert communities.
Morning sun	Good light; not as hot and intense as afternoon sun.   Fine for plants that like partial shade.	Ribes, Heuchera and many other north-exposure plants tolerate this exposure.  Plants from sunny canyon slopes,
High/Dappled Shade	Shade created by tall, open trees or a north-facing wall. Fairly bright light, but direct sun is minimal for any length of time.  A wonderful type of light!	Hospitable to many sun and shade loving plants from nearly all plant communities.
Part-shade/ Shade	No direct sun for at least half the day.  Darker than high shade – often on N side of taller buildings or dense trees.   Shade-loving plants.	Shade-loving plants, primarily understory plants from Oak Woodland, Riparian and Forest Communities.
Deep shade	Quite dark the entire day - for example, under very dense evergreens.  Not much grows here.	Forest floor plants that require very low-light conditions.  More likely plants from Pacific Northwest, other heavily forested regions.

Average temperatures and precipitation (ref 1)

3. Temperature and Temperature Patterns

Local temperature information is readily available on the internet for many areas. One of the best resources is US Climate Data: https://www.usclimatedata.com/. We suggest downloading a table/graph of the average monthly high and low temperatures for your local area. This will help you realistically plan your garden. It will also let you know when you’ll likely be able to plant in your area. (ref 2)

Plant Hardiness Zone for Mother Nature's

 Montrose Garden: 6b

Another important resource is the USDA Plant Hardiness Zone Map (https://planthardiness.ars.usda.gov/PHZMWeb/).  You can now access Hardiness Zone information, on the internet, by simply entering your Zip Code.  According to the USDA website (ref.3):

“Hardiness zones are based on the average annual extreme minimum temperature during a 30-year period in the past, not the lowest temperature that has ever occurred in the past or might occur in the future. Gardeners should keep that in mind when selecting plants, especially if they choose to "push" their hardiness zone by growing plants not rated for their zone. In addition, although this edition of the USDA PHZM is drawn in the most detailed scale to date, there might still be microclimates that are too small to show up on the map.”

As with precipitation, temperature can vary greatly over short distances. In fact, each garden has its own temperature microclimates, influenced by buildings, walkways, plants and physical structures as well as wind, shade and other factors. You may have already noticed areas that are warmer or cooler than the rest of the garden. You can use temperature microclimates to your advantage by planting plants that require more – or less – heat than is found in the rest of the garden.

Get out into your garden and notice the temperature patterns. If it’s summer, now is a good time to discover pockets of heat in the garden. If it’s winter, observe which areas are noticeably warmer or cooler (there may be as much as 10° F (5° C.) differences across the garden). Note the differences on your Site Summary Sheet and map the areas on your map (see example from a small garden, below).

4. Topography and Drainage

Landscape topography refers to the high and low places in the garden. High points may be as dramatic as actual hills or the tops of steep slopes. More often they are subtle, representing elevation changes of only a few feet. Low places in some gardens may include natural canyons, streambeds or the bottoms of steep slopes. In many gardens the low areas also are subtle – but they are enough to affect drainage patterns. The topography may be either natural or man-made.

Landscape topography is most important for its effects on soil moisture. You may have noticed low areas in your garden that tend to retain moisture longer – or high areas that dry out more quickly. You’ll want to take advantage of these differences in topography by planting species appropriate for the soil water conditions they provide. The first step, of course, is to map significant garden topography on your Physical Features Map (see example, below).

5. Wind Patterns

Wind can play an important role in some gardens. Some areas have high winds at certain times of the year. Other areas may have cooling mountain breezes most afternoons. Still other gardens may experience hot, dry winds in the fall or spring. All of these wind patterns may influence the type of plant that will thrive in your garden.

Wind also provides air circulation. This is often a good thing, particularly in gardens where soil moisture can provide the perfect conditions for garden fungi during warm weather. Get out in your garden and observe wind/air flow patterns over several days. Be sure to observe these patterns at different times of the day. Are there areas that are particularly breezy? Areas where the air doesn’t move at all during the day? Map these on your Physical Features Map.

Think about the yearly patterns of wind in your area. Are their times of significant high winds? Have these effected local gardens in the past? Note this also on your Site Summary Sheet. You’ll need to plan for wind when you design your garden and choose your plants.

Warm- and cool-season wind patterns:

Mother Nature's Montrose Garden

Above is a map showing the warm and cool season wind patterns in Mother Nature’s Montrose Garden.  Strong winds do blow through the garden, particularly in May/June and October.  Winter storms can also bring strong gusts.  We’ll need to consider this when choosing and placing our plants.

We do get occasional summer hail!

6. Snow and Hail 

If you live in Colorado (or any other place that gets snow and hail) you should consider these factors in planning your garden.  Fortunately, we don’t often get severe hail storms in Montrose.  If you live in an area that does, note the months and garden areas most impacted on your Site Summary Sheet.

If you live in a cold climate, snow may build up in colder (shadier) parts of your yard.   Snow may melt slower in these areas in the spring.  This information can be useful in garden planning.  If these conditions occur in your garden, note them on your Physical Features Map and Site Summary Sheet.

7. Other Physical Features

Other physical features include anything else that will influence your landscape design. These will vary greatly from site to site. One yard may have commanding vistas that should be featured in the landscape design. Another may have unsightly views which should be screened. These features (and any other physical features) should be mapped on your Physical Features Map. 

Some sites have unique physical features that could be highlighted in the garden design. These include cliffs, large rocks/boulders, natural outcrops, ponds, streambeds and many other features. You may want to design your entire garden plan around significant physical features. Include any such features on your map.

Be sure to join us next month, when we'll help you plot out the types of activities you want to do in your Colorado-friendly garden.  You might start listing things right away!

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1. https://www.usclimatedata.com/climate/montrose/colorado/united-states/usco0275
2. https://www.usclimatedata.com/
3. USDA Plant Hardiness Zone Map, 2012. Agricultural Research Service, U.S. Department of Agriculture. Accessed from https://planthardiness.ars.usda.gov/.

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We welcome your comments (below).  You can also send your questions to: monaturesmontrosegarden@gmail.com