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Eco-friendly maintenance of annuals planted in the ground

They embellish flower beds, showcase perennials, and protect vegetables from harmful insects: annuals are a must in any garden!

Easy to grow, most annuals will bloom abundantly throughout the spring and summer and often well into the fall as well. They come in a wide variety of colours, shapes, and sizes, offering endless possibilities to enhance your garden. Find out how to choose annuals and how to properly care for them.

The remarkable qualities of annuals

Annuals have a lot of qualities that make them an excellent choice for your property.
  • Their early blooming produces an immediate impact in the garden.
  • Their abundant and continuous blooming keeps beds colourful throughout the season.
  • The wide number of varieties makes it possible to vary colours and layouts every year at relatively little cost.
  • They require very little maintenance and are not invasive.

The use of annuals in the garden

No matter the style or layout of your garden, you can use annuals either alone or in groups for a variety of purposes:
  • Produce spectacular effects by selecting plants of different shapes and heights arranged in groups.
  • Draw attention to specific areas of the garden.
  • Fill empty spaces in a new perennial garden.
  • Provide continuity between flowering periods of perennials and ornamental shrubs.
  • Create beautiful planters, flower boxes, and hanging baskets.
  • Create the effect of a flower bed by grouping annuals in containers around a swimming pool or hot tub.
  • Embellish the vegetable garden while helping to protect vegetables from insect pests.
Try to limit the number of colours in flower beds for a striking visual effect and a more harmonious overall look.

The right choice of annuals

It's important to choose good-quality annuals so that they recover quickly after planting out and continue to grow well.
To choose annuals, make sure that:
  • They are vigorous, compact, and well-branched out
  • The foliage is lush and green, with no spots, insects, or signs of disease
  • The root system is well established
  • The plants have only a few flowers open or none at all. This will enable them to recover as quickly as possible after planting.
You can either start your annuals from seeds or buy them from a garden centre in flats or cells. You can also purchase finished products such as planters or patio containers to enhance a balcony, patio, or small outdoor space.

Some tips for planting out annuals

Annuals need to be planted out properly in order to grow healthy and strong. Here are some important tips for ensuring success.

Preparing the soil in the flower bed

Annuals usually require a fertile, loose, and well-drained soil. Prepare the soil when it is fully thawed and dry enough to be worked.
  • Turn the earth over to a depth of 45 to 60 cm, using a spading fork or a rototiller to loosen it. During this procedure, remove the weeds.
  • Spread and lightly incorporate 5 to 7 cm of organic matter such as compost, peat moss, or manure. You can also use a good-quality soil mix designed especially for annuals and perennials. These mixtures generally contain compost, peat moss, humus, and perlite.
  • A supplement of Gaspesian seaweed meal or bone meal is excellent for root growth.
  • A slow-release natural fertilizer containing alfalfa or crustacean meal can be worked into the soil to improve its quality and provide plants with nutrients throughout the season. You can also use a slow-release fertilizer of type 4-8-4 to maintain vigour and continuous blooms.

Planting steps for growing annuals in flower beds

  • 1 - Water the annuals at least one hour before planting.
  • 2 - Remove all flowers as well as yellow or damaged leaves to promote rooting.
  • 3 - Pinch the ends of plants that are too high to help them branch out and to also promote rooting.
  • 4 - With a sharp knife, slice down through the roots to separate the plants in the box.
  • 5 - Remove plants from pots or cells by turning them upside down, taking care not to disturb the roots.
  • 6 - Cut off a third of entangled roots and gently free them before planting.
  • 7 - Plant annuals according to the spacing indicated on the label. Generally, 10 to 20 cm of space between plants is recommended.
  • 8 - For a more natural effect, plant the annuals in a zigzag pattern.
  • 9 - Using a garden trowel, dig the planting hole slightly bigger than the root ball.
  • 10 - Delicately place plants in the holes, ensuring that the top of the root ball is at ground level.
  • 11 - Water deeply after planting and then regularly until full recovery of the plants.

The required care

Keeping your annuals looking healthy and beautiful will require some care and maintenance over the season. Here are the main maintenance tasks you need to stay on top of.


The fertilization needs of annuals vary depending on the species. Some annuals actually prefer poor soil; in an organically rich soil, plants such as fragrant alyssum, nasturtiums, cosmos, and treasure flowers will produce luxuriant leaves but very few flowers. Annuals like these should, therefore, only be fertilized at the time of planting. This is why it is important to know the needs of each type of annual and to check them regularly during the growing season so as to adjust their fertilization if necessary.

One treatment in spring and another one in summer is usually enough for plants that require fertile soil. These inputs of nutrients allow needy plants to bloom abundantly throughout the season. You can use the same fertilizers as those mentioned in the section above on "Preparing the soil in the flower bed."

Watering and mulching

Annuals may require watering during the growing period. Flowers will also suffer if they are not watered during long dry spells. In general, annual plants need about 3 cm of water per week, be it from rain and/or additional watering.
  • Check the soil moisture at a depth of 7 to 10 cm.
  • If necessary, water deeply: the deeper the root system, the more plants can resist summer heatwaves.
  • Avoid frequent surface watering. This will promote a superficial root system, thus making plants less resistant to drought.
  • If possible, water in the morning to allow foliage to dry quicker. However, if local by-laws only allow watering in the evening, it is advisable to water the ground directly instead of wetting the foliage to prevent disease from developing. To do so, use a soaker hose and a timer to avoid water wastage.
A natural way to preserve soil moisture after planting annuals is to apply mulch. Mulching flower beds protects sensitive plants from drought while preventing the establishment of weeds. The use of organic mulch also provides organic matter while activating life in the soil as it gradually decomposes.


Hoeing consists of loosening the soil at a depth of 3 to 4 cm. This procedure improves air and water circulation in the soil while destroying annual weeds by lifting them to the surface of the soil, where they die.


Pinching consists of removing the new growth at the end of a stem to obtain fuller plants with more blooms. For plants grown for their foliage, e.g. coleus, pinching allows them to branch out and also encourages richer colours and denser leaves.

Pinching should be done when plants:
  • Begin to grow again
  • Have developed several pairs of real leaves
  • Have reached 5 to 10 cm high.
How to pinch a plant: Take the end of the shoot (above the last pair of leaves) between your thumb and forefinger and pinch it to remove that portion of the stem. Repeat every 6 weeks for pansies, snapdragons, marigolds, petunias, and cosmos.


Regularly removing wilted flowers encourages the growth of new flowers. Therefore, the plant does not waste energy on producing seeds. Annuals such as petunias, gaillardias, marigolds, geraniums, snapdragons, zinnias, verbenas, and dahlias will benefit from deadheading every 2 to 4 weeks.

Cutting back

Around mid-summer, annuals may start to decline. To revive them, simply cut the stems back down to a third of their height. New flowers will start to emerge after two weeks, and the plant should continue flowering until the first frosts. The following annuals benefit from being cut back: nasturtium, fragrant alyssum, marigold, ageratum, lobelia, and petunia.


Some tall annuals or those with heavy blooms (e.g. cosmos, giant dahlia) need to be staked to resist the wind. Insert the stakes early in the season and tie the plants as they grow.

Stakes are generally made of wood or bamboo and should be 10 to 20 cm shorter than the plant’s height at maturity. Place the stake as close as possible to the stem without hurting the roots. Drive it into the ground behind the plant. Attach the stem to the stake with string, every 30 cm or so.

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