Annuals
Annuals in the Landscape
Annuals are plants that are alive for one growing season only. Either they naturally complete their lifecycle in 1 year, or they are killed by weather at the end of the growing season. When you need a quick, intense dose of color in the landscape, annuals are a good choice.
The most interesting and resilient landscapes often have a mix of plant types: herbaceous perennials, shrubs, trees, and annuals.
Here are some tips to using annuals in your landscapes:
- Adding seasonal color to containers
- Adding color to perennial border gardens in periods where there isn't much blooming—this is common in early spring, winter, or fall
- For large displays of intense color in beds
- Cut flowers or companion plants in vegetable gardens
- Providing habitat to beneficial insects
- Color contrast with perennial plants
- Plant options for tough, droughty locations
Some annuals thrive in cooler weather, but others are adapted to hot weather. Species will vary in their need for water, but in our area all will need some sort of irrigation. Most annuals do better planted in good soil with a couple inches of organic mulch material.
Growing Annuals High Desert
In the Eastern Sierra the high desert areas have the most options in growing annuals. This region has 2 distinct growing seasons: warm season and cool season.
Because summers are hot, warm-season annuals are planted when frost season has passed and the soil warms. These plants typically are removed in October.
Common warm-season annuals grown in our area include: annual vinca, petunias, annual salvia, marigolds, and wax begonias. (This list is not comprehensive.) Houseplants and tender plant species with interesting foliage are also options if you have an appropriate location.
Beginning in late summer or early fall, cool-season annuals can be planted. These species do not tolerate summer heat, but are okay with moderately cold weather. In the Owens Valley we usually see snapdragons and pansies planted in fall.
Colorado State University runs a trial garden to test species in the High Plains. This is probably the best resource to find out about more options of plants suitable for the high desert in eastern California. http://www.flowertrials.colostate.edu/
Growing Annuals in the Mountains
High elevations such as Mammoth Lakes and Aspendell have a very limited growing season. Frosts and unexpected weather make planning difficult, but on a positive note: the cooler temperatures make plants just as happy as people!
Generally, you can plant any cool-season annuals in the summer in the mountains. Certain warm-season annuals also do well once summer weather arrives. Good warm-season choices include petunias, marigolds, geraniums, and annual salvia. Cool-season plants have some more exciting choices: larkspur, snapdragons, pansies, stock, salpiglossis, osteospermums (bone daisies) and fuschias like our high-elevation summers. Be ready to protect any annuals from surprise cold snaps or hail. In all cases due to the short growing season, try to use plants already in bloom.
Thankfully, if the plants are destroyed, they do not comprise a permanent part of your landscape and can be easily replaced. You would do that annually anyway!
Growing Annuals in the Low Desert
Inyo County has several low desert locations that may want to try growing annuals. Because the summer heat is so intense, yet the winters are mild, the timing for annual plants in the landscape is very different than other areas.
In winter the best choice is usually cool-season annuals that can tolerate some heat. Snapdragons and pansies are acceptable choices, although many petunias will do fine as well. Since winter doesn't last long, expect the season to be short.
To help deal with the transition to hot weather, you can interplant beds with more typical warm-season annuals about 5 or 6 weeks after planting the cool-season plants. In frost free locations, you can plant most warm-season annuals in fall after the intense summer heat has abated.
If you want to plant annuals for summer, there aren't many choices that can tolerate the heat in the nursery trade, and those that can will likely need a lot of water and a shaded location. If you're looking for summer interest, you will be more successful with desert-adapted plants. The California Native Plant Society can advise on choices.
The University of Arizona has a guide to herbaceous low desert landscape plants. Download the guide here → Flower Planting Guide for the Low Desert
Keep in mind that our low desert communities usually have terrible soil. Planting annuals in containers will help. Use an air gap between the ground and the container to keep salt from wicking up into the container's soil.