Grouping plants according to their water needs is a challenge for gardeners particularly during drought conditions.  The rate at which plants use water is called evapotranspiration or ET.  Temperature, humidity, wind and light all influence the ET rate.  When watering, we need to replace the amount of water that has been lost due to ET.

The amount of needed water listed on plant labels is not clear; for example, how much water is "moderate" or "dry"?    Nurseries and garden centers help by placing these plants in a "xeriscape" area.  Another method of categorizing plants according to their water needs is the  "X-rating" system that is being implemented to heighten our drought-tolerant awareness and increase gardening success.  Garden centers are labeling plants with one X, two X's or 3 X's depending on how xeric or drought tolerant the plant.  They are also offering the X-rated plant brochure published by Garden Centers of Colorado so shoppers can locate drought tolerant plants with low-water needs.  The brochure lists annuals, perennials, shrubs, vines, trees, grasses, and evergreens.

Remember that water requirements are for established plants.  All plants, regardless of how drought tolerant they will be when they are established, will require additional moisture for at least the first year after transplant.  Drip irrigation, soaker hoses or hand watering will best control the total volume of water being applied.

In addition to drought tolerance, check out plant labels for light needs and soil preferences.  Plants with similar light, soil and water needs should be grouped together for the greatest success.

Full-sun means a minimum of 6 hours of direct light, such as open areas or southern exposures.  Part-sun plants do well in filtered or dappled sun areas for the majority of the day.  Remember that morning sun is not as intense as the afternoon western exposure.   Shade plants require less than 2 hours of sun or indirect light on the north side of the house or deep shade under evergreen trees.  Part sun/part shade plants will flourish under a wide range of conditions, but cannot perform under extreme sun or shade.

Soil preferences are identified in physical terms (sand or clay, deep or shallow) or by chemical compound (acid or alkaline, or fertile or infertile) but not all plant labels indicate soil preferences.

Most Front Range soils are high in clay or sand.  They are usually high in alkaline, lacking organic matter, and it is possible to have both in the same landscape.   Plants, shrubs, trees, and vines require garden soil with amendments like peat moss, compost or other organic material for maximum water efficiency. Amending and preparing the soil is easier to solve before rather than after purchasing plants.  Applying mulch reduces evaporation, retains moisture in the soil and controls weeds.

Fertilizers and organic matter can change the pH over a period of time; however, the successful garden will have plants adapted to the alkaline soils prevalent in the region. Other variables to consider in planning the right plants for the right place include slope, drainage and wind exposure.

Look for "keys" in your favorite gardening catalogs and learn how to read and understand the USDA Hardiness Zone map. Also become familiar with heat zone maps, look for Plant Select winners, find out what the neighbors' successes have been and ask the staff at the local gardening center.

The Larimer County Office of Colorado State University Cooperative Extension takes calls and provides Fact Sheets of drought-tolerant plants, soils and amendments, mulches and additional drought information for the Front Range. You can also download fact sheets directly from our web site.

Q: Are pansies easy to grow?

A: On chilly nights and in chilly weather, the pansy keeps right on blooming when temperatures dip to the 20's.  They are the perfect plant to liven up the garden during times when little else is in flower. Pansies have few disease and insect problems and are quite versatile.  Their vibrant rainbow of available colors can be massed in beds, potted as an accent, worked in as a border and they can stand-alone.   Pansy petals are edible and add color to salads. There are around 150 varieties and many are perennials.  Most pansies are treated as annuals and they do need a few hours of sun each day in order to flower well.  Pansies will not tolerate the heat of full summer sun.

Q.  I am aching to caress the good earth and smell things growing.   My garden is soggy and many of my plants are emerging tender shoots.  Is it too early to work the soil?

A.  The urge to get out and dig, rake and cultivate is fearsome for us gardeners, but walking on the soggy spring soil compacts the earth and destroys the structure of the soil.  To be sure the soil is workable, grab a handful of soil and squeeze.  If water runs out or the soil stays compacted in one sticky lump, it is too wet to work.

Q.   When is the best time to plant annual and perennial gardens?

A.  Spring is officially here.  In Colorado, one day the sun shines, the next day it snows and the weather turns cold.  We have had very warm days of sunshine and there is a profusion of plants in the garden centers.  Along the northern Front Range, the average last frost date is May 10 to 15.   However, native residents have seen snow as late as Memorial Day.  Fragile plants stuck into the ground too early will have their young lives cut short in one final May snow or heavy frost.  Even if they don't succumb to killing cold, the small plants will eke out a pitiful existence while waiting for the dirt to warm up.  The best remedy for the planting urge is to put your initial energy into your soil and a garden plan.  Do some prep work with the ground so the plants will have a place to root rather than drying out on the patio while their owners try to figure out what to do with them.    Not only does the ground need to be ready, but also the gardener needs to be ready.  Know what plants you are looking for in order to avoid impulse buying.

Keep spring blooming bulbs like tulips and daffodils from going to seed by removing the blossoms (deadheading) as they fade.  Allow the foliage to grow and die back naturally.  Fertilize with 5 lbs. of 5/10/5 fertilizer per 100 square feet if you plant annuals among the bulbs.

Asparagus is one of the few perennial vegetables that may suffer some frost damage on the tips if the weather gets cold.  It usually takes 2 to 3 years to get an asparagus bed established before you should start picking.

Start seeds of summer and winter squash, cantaloupe, watermelon and pumpkins so they will be ready to transplant into the garden at the end of the month.  Look for bush varieties that could be grown in containers and use less water.  There is even a "semi-bush" pumpkin called Frosty with short 5 foot vines.

May 1st  was a few days ago but during the Middle Ages May Day was observed on May 12th.  Young men and women gathered flowers and boughs to decorate the Maypole, a symbol of hope for a plentiful harvest.

The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.

Gardening and Insect Fact Sheets are available on-line by clicking HERE.

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This page updated:  April 29, 2003