The culture and maintenance of annuals

The culture and maintenance of annuals

Filled with colors and so many varieties, annuals will jazz up your garden all summer long.  They will allow you to create original landscaping settings reflecting your personality and style.  An immediate and spectacular impact guaranteed.  Because annuals cannot survive our winter climates, you have the opportunity to create a new decor each year.

Planting annuals under trees will help decorate shaded areas.

Mix them up with perennials to create some movement and vigour in your flower beds.  Create a particular focus on your terrace by coupling them in beautiful containers, bins, flower boxes or hanging baskets.

Plant Selection

The key for a successful cropping season is to put the right plant in the right place.  This motto applies whether you work in containers or in flower beds.

In a unique container or in flower beds, group annuals that have similar requirements, such as:

  • Sun exposure.
  • Sun intensity (noon, 10:00 am to 2:00 pm).
  • Shade and winds.

For places:

  • Sunny and windy areas, such as balconies, choose resistant varieties such as petunias and geraniums.
  • For northern or shady areas, choose plants adapted to shade and moisture tolerant such as impatiens, fuchsias and begonias.


Making a good selection will bring better results and the plants will be less affected by insects and diseases.

Planting Annuals:  How and When


An easy rule to follow: you can start planting as soon as there is no risk of frost on the ground.  For the Montreal region (hardiness zone 5), you can start at the end of May.  In zone 4 areas like Granby, Drummondville, Joliette or Saint-Jérôme, push the date one week later in early June.  In a zone 3 area, and further North, again push another week to mid-June.

Some people say that you can plant with no fear after May’s first full moon.  By experience, this rule is quite correct.

If your annuals are planted and that a risk of frost is announced, you can easily protect your plantations by covering them with a bed sheet that will keep soil heat to stay near your plants.

Another tip is:  a good watering can protect the plant from the cold.  Certain annuals tolerate cold during spring :  petunia, Osteospermum and pansies.

When to Plant Annuals in Containers

Step 1: plow the soil about 30 cm (12 inches). Add in equal parts potting soil and mix well.  Dig a hole approximately the same length as the container and one and one half to three times its width.

Step 2: compress the container and tap out the plant.  Delicately free the roots with your fingers.  If the roots are too dense, liberate the fibres by inserting a knife or a transplanter.  Separate the roots carefully, then place them in the hole.

* Good to know:  use organic bone flower, a soil activator or a starter fertilizer ‘’Kick Start’’ when transplanting to stimulate a good root development.  Follow the instructions on the product label.

Fill up the hole with garden soil.  Slightly press the soil around the base of the plant to help the roots contact with the soil.  Water regularly every 2 or 3 days until the soil is well compacted.

You can prepare your containers and flower boxes as of mid-May.   They will be allowed to definitely stay outside only once the exterior temperature reaches a definite 10oC.  Meanwhile, you can store them in the garage, garden shed or under a patio during cool nights.

Container Types

You can find many types of plant holders in the market:  many sizes and shapes of containers, hanging baskets or urns, generally made out of plastic, terra cotta, cement, cultured stone, etc.   They are many varieties for every taste and budgets.

* Good to know: for sunny areas it is preferable to consider using light coloured containers.  Dark color containers will absorb more heat and therefore require more watering.

Prefer large and deep containers which will offer your plants a larger water reserve.  The more the container is small the more you will need to water.

  • Patio container – more than 30 cm in diameter.
  • Planters – more than 25 cm.
  • Flower box – more than 25 cm in width.

To allow evacuation of water surpluses (rain or watering surplus), make sure your containers have one or more drainage hole.  If not, make a 1.5 cm dia. hole every 25-30 cm.

If you want to leave your containers outdoors during winter, ensure they can resist to frost.  Privilege cultured stone, cement, metal, plastic or wood.  All terra cotta containers must be stored during winter.


A good soil must retain water and nutritive elements.  Use a good quality, rich and airy breeding ground.  You can make your breeding ground starting with peat moss, compost, perlite, etc.  Certain commercial soil are specially developed and guarantee the growth and flowering of annuals in containers.

Select a substrate for plants in containers that contains the following characteristics.

  • Good water retention.
  • A start-up fertilizer.
  • Crystals (polymers).

Such crystals will allow for a good water absorption and storage and then will liberate when the soil becomes dry.


Bedding Grown Preparation

  • Mix the bedding grown in a large container or wheelbarrow.
  • Humidify the ground, without soaking the soil before putting it in the containers.
  • Add a natural fertilizer (seaweed or feather meal) or a fertilizer with a slow release, formulae close to 4-8-4.  Always follow the manufacturer’s dosage recommendation.

Filling Up the Container

  • Check for drainage holes at the bottom of your container.
  • Fill the container up until its 2/3rd with the humid ground.
  • Compact the soil by delicately hitting, once or twice, the container on the ground or on the working table.
  • With your hands, delicately press the soil on the sides of the container.
  • Do not compact the soil in the center, it could slow down the root growth.
  • Complete until you fill 2 to 3 cm to the edge of the container.

After planting or watering, re-adjust the soil’s level if necessary.

Plant Preparation

  • Arrosez les plants au moins une heure avant.
  • Retirez toutes les fleurs fanées, les tiges mortes et le feuillage jauni (favorise l’enracinement).
  • Taillez toutes les tiges étiolées de moitié, et ce, même si elles ont des fleurs. Cette opération favorisera le développement de nouvelles pousses augmentant ainsi la floraison. La taille des tiges étiolées peut se faire aussi une fois les annuelles plantées.
  • Retirez du pot et faites 3 à 4 incisions sur la motte à l’aide d’un couteau lorsque les racines sont enroulées dans le pot. Les dégager délicatement en prenant soin de ne pas défaire la motte. Cette méthode stimule la formation de nouvelles racines et facilite l’intégration de la plante dans son nouvel environnement.


As per your sketch or desired arrangement, start planting by the center and finish with the borders.

Make holes in the ground and add micorrhizae at the bottom of each hole.  Micorrhizae is a beneficial fungus that helps draw the less accessible nutrients and promote a better water absorption augmenting plant’s resistance to stresses such as drought and salinity.

Place the plant crown (where the stem meets the roots) at the same height than it was in its original container.  Add soil around the plant and pack without compacting.

Leave enough space between each plant allowing them to better develop and bloom.  You can divide in two the recommended distance mentioned on the tag.  A  10 to 20 cm spacing is appropriate for most annuals in containers.

Some annuals, more vigorous or with a large deployment require more planting space (ex:  Surfina at 30 cm).

Once completed, slowly water the soil, 2 or 3 times until the water flows by the drainage holes.



Before watering, double check, by pressing your finger into the ground, if it is necessary to water your plants.  If the soil is humid, close to the roots, no need to water.

The ideal time to water your plants is in the morning.

Before using a fertilizer or soil improver, carefully read the instructions on the label of the product and follow the recommendations.

You should pay special attention to the instructions and precautions to take before, during and after using a product, also to the recommended storage conditions.