The Guerrilla Gardening Guidebook – Annuals


“Moonflower” – Whitney Avenue – Wilkinsburg, PA – Datura wrightii… Sacred Moonflower that was given as a gift a few years ago… Frost kills it to the ground… Depending on how harsh of a winter I have it typically sprouts again in spring… This plant also creates a ton of seeds making it a perfect plant for vacant lot gardening…


This post is part of a larger body of work titled ”The Guerrilla Gardening Guidebook”. For the introduction and table of contents please click here

Every guerrilla gardener dreams of a wall of color growing in place of litter and blight, nothing can match the flash and glitter of a profusion of flowering annuals when a statement is to be made.  When it comes to sheer flower power, no other plant matches up to these prolific bloomers.

Many garden annuals bloom practically nonstop from late spring or early summer, only stopping with the killing fall frost. By definition an annual plant lives for only one year, completing its entire growing season in one year. It germinates, develops into a mature plant, blooms, sets seed, and finally dies… All in a span of several months…

Some annuals, especially hardy ones such as sweet alyssum and larkspur, can reseed in your garden. They may come back the next year without even planting them. This can be a good thing, or a disastrous situation depending on what you are dealing with. Many self-seeders are borderline invasive if not full-blown invasive. Amaranth comes to mind, setting millions of seeds that seem to sprout legs and walk all over the neighborhood. Research and experience will help determine your problem plants, deadhead your flowers before the seeds fully develop.

Most annual plants die because of a hormonal trigger set off by seed formation or ripening. Gardeners can trick this natural phenomenon, at least for a time, by continuously removing the dead flowers… AKA Deadheading… By preventing seed formation, deadheading encourages the annual to continue blooming an a desperate attempt to set seed… Sometimes this will promote blooming in an overachiever… Some modern annuals are sterile and do not set seed, they typically bloom right up until frost without any human intervention.

Impatiens, petunias and marigolds are probably the most popular garden annuals sold today… Probably too popular because I see them everywhere… I swear to God I can tell you what annuals home depot stocks just by walking through a suburban neighborhood. I can also typically tell you who shops at privately owned nurseries… The world of available annuals is constantly expanding, though I recommend the standards for guerrilla gardening due to the issues associated with maintenance.

Not all annuals are created equal as far as temperament and growing requirements are concerned. Annuals can be classified into several broad categories, all with different characteristics. Knowing the specifics of the annual you are planting helps you understand the plants habits and needs.


“Pineapple Sage” – Whitney Avenue – Wilkinsburg, PA – Stunning pineapple-scented gold foliage covers this plant through the summer months… As fall approaches… Pineapple Sage begins stretching towards the low sun followed by a display of red flowers often unmatched in the autumn garden…

Tender Perennials – Many of the annuals sold at the typical garden center are actually tender perennials. These are long blooming perennials in their native habitats… But the cold of winter… Not their genetic makeup, kills them in the winter… So they behave like annuals when grown in the north…

Warm-Season Annuals – Flourishing in heat and blooming best in summer, warm-season annuals like zinnia, marigold, and cosmos cannot survive even a light frost. Freezing temperatures kill tender seedlings and sometimes seeds. Because plants take several months to mature and begin flowering, you may want to start your seeds indoors.

Cool-Season Annuals – Nasturtium, sweet alyssum, pot marigold, and other cool season annuals flower best during cool weather and wither or die in during summers heat. Freezing temperatures usually do not kill seeds, which often self-sow and overwinter in the garden, sprouting in spring or summer. In temperate regions, early planting provides the best show from cool-season annuals… Allowing them to bloom until the heat of summer…

Hardy Annuals – This type of cool-season annual withstands the most cold. Sow the seeds in spring before frost danger has passed or in late fall for spring germination. Hardy annuals include Iceland poppy, pot marigold and larkspur.

The following are annuals tolerant of guerrilla gardening conditions…

Snapdragon, Begonia, flowering kale, pot marigold, periwinkle, bachelor’s-button, cornflower, Cleome, coleus, larkspur, cosmos, annual dahlia, dianthus, California poppy, Annual Blanket Flower, Sunflower, Strawflower, Heliotrope, Impatiens, Lantana, Sweet Pea, Lobelia, sweet Alyssum, Flowering Tobacco, Corn poppy, shirley poppy, Flanders Poppy, Geranium, Perilla, Petunia, Annual Phlox, Moss Rose, Zinnia, Marigold, Nasturtium, Verbena, Pansy.

Planting should be done on a cool cloudy day, rain in the forecast can be a huge help whenever possible. Water the cell-packs so the plants slide right out. If they do not, push the bottom of the cell with your thumb, and the roots should pop right out. Well grown annuals will have a network of white roots growing around the soil ball.

A root bound plants roots should be broken apart before transplanting, this encourages the roots to grow out into the soil as opposed to continuing around in a circle. Gently split the matted root ball up the middle by pulling with both hands in opposite directions and untangling as many roots as possible.

Water immediately after planting… Because the plants are young with relatively tiny root systems, you may need to water every day for a few weeks until everything gets established. Annuals that are allowed to wilt at this stage of their life, often suffer for a considerable amount of time after.

plant petunias and question everything – chriscondello

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