The light available to a plant will directly impact its success in your garden. Understanding the light conditions before you select plants will make you a savvy buyer.
Most plant tags will have some indication of whether the plant requires, full sun, part sun, part shade or shade. If you aren’t sure, take the time to check before you buy. These terms have a general meaning in horticulture. Full sun is six or more hours of direct sunlight per day, part sun is four to six hours per day. Partial shade is two to four hours of direct sun per day, shade means less than two hours of direct sun.
A useful exercise is to actually measure the amount of direct sun each hour, and record it for several different parts of your garden. Start at 7 a.m. and go to 7 p.m. preferably in June or July. You may be very surprised at how much more understanding you will gain. You can purchase instruments for measuring the light, but for the home gardener your observation is probably just as useful. Another factor is the time of day of the sun. Shade plants are more likely to tolerate some sun in the early morning, but not the hot afternoon sun. Plants that get too much sun can appear bleached, or even scorched. If you notice these signs either relocate the plant or create some additional shade with a structure or perhaps a shrub or tree nearby. Plants that do not get enough sun may not flower abundantly, and will look spindly and weak.
Be aware that sun conditions can change as your landscape matures. Trees that once cast little shadow, at maturity will shade much larger parts of your garden. Likewise, if trees are removed then a shady area can be suddenly sunny.
Plants vary widely in terms of light needed and tolerated. Shade plants are anatomically adapted to be more efficient at photosynthesis in limited light. Many shade plants feature thin, but large surface area leaves. By weight they contain more chlorophyll than their sun loving counterparts. Think about plants like hosta, coral bells and ferns, these are plants most valued for their big, colorful foliage. Sun loving plants in general have thicker but smaller leaves. Think of plants like roses, succulents and coneflowers.
If you are looking for good ideas for plants in any category take a look at PlantSelect.org. This program is a collaboration between Colorado State University, Denver Botanic Garden and professional horticulturists. Plant Select tests and evaluates plants for their success in Colorado. The website includes a searchable database of plants that have been tested for success in Colorado. It is a great resource for plant selection.
Planning for light conditions is a practice that will enhance your gardening success.
When you have questions, Colorado State University Extension has research-based answers Get answers to your horticulture questions by calling a Master Gardener Volunteer at 719-520-7684 or emailing CSUmg2@elpasoco.com. Volunteers are available to help you Monday to Thursday from 9 a.m. to 12 p.m. For current garden tips visit Facebook.com/ColoradoMasterGardeners.EPC. For current classes visit ElPaso.Extension.Colostate.edu/.