Many “annuals” in our gardens are not true annuals. Instead, they are “tender perennials.”: perennials from subtropical or tropical climates. If they die in the fall, it’s not because they have reached the end of their life cycle (as is the case with true annuals, all of which die at the end of their first year), but because they are exposed to killing frost. They are, in fact, can live for years in mild-winter areas. That means you can save these plants at the end of the season by bringing cuttings of them indoors … where tropical temperatures reign.
The time to take cuttings of annuals to bring indoors is, most climates, in late summer or early fall, just before nights start to cool down.
Success With Annual Cuttings
Using pruning shears, a sharp knife or scissors, cut off a section of stem about 4 in/10 cm long (smaller annuals) or 6 to 8 inches/5 to 20 cm long (taller plants).
It’s wise to next dunk the cuttings in soapy water then swish them around for a second or two to kill often any bugs that might be hiding there.
Also remove a few leaves at the base of the cutting, especially any that would be buried when you pot the cutting up.
Now, “pinch” (clip off) the upper tip of the stem to stimulate better branching.
For woody or semi-woody plants, such as hibiscus, pelargoniums and fuchsias, apply a rooting hormone (available in garden centers) to the lower part of the stem. In the case of soft-stemmed plants (begonia, impatiens, petunias, etc.), no hormone is required.
Insert the cuttings into a small pot filled with moist potting mix. Cover the cuttings with a plastic bag or a transparent dome to create a “greenhouse effect” beneficial to rooting. Now place the cutting in front of an east window, back a bit from a south or west window, or under a fluorescent light illuminated 12 to 16 hours a day.
After 2–8 weeks, when you see new leaves appear, remove the dome or bag: the emergence of new growth shows that the cutting is rooted and has now become an independent plant. At this point, you may need to move the plant to a sunnier window, depending its needs (most flowering plants prefer full sun indoors during the short days of fall and winter).
Care for your now-rooted plants over the winter by watering and fertilizing as needed. Up the humidity if possible by growing them on top of a humidity tray. When spring comes around again, take cuttings from your cuttings and you’ll soon have plenty of “annuals” to put in your garden!
Annuals You Can Grow From Cuttings
A surprising number of so-called annuals can be grown from cuttings, including the following plants:
- Ageratum or floss flower (Ageratum houstonianum)
- Alternanthera (Alternanthera spp.)
- Angelonia (Angelonia spp.)
- Bacopa (Sutera cordata)
- Begonia (Begonia spp.)
- Browallia or amethyst flower (Browallia spp.)
- Calibrachoa or Million Bells (Calibrachoa spp.)
- Coleus (Plectranthus scutellarioides, formerly Coleus blumei)
- Copperleaf or red-hot cat’s tail (Acalypha spp.)
- Cuphea, firecracker plant or cigar flower (Cuphea spp.)
- Diascia (Diascia spp.)
- Duranta (Duranta spp.)
- Euphorbia (Euphorbia spp.)
- Flowering maple (Abutilon × hybridum)
- Fuchsia (Fuchsia spp.)
- Heliotrope (Heliotropium arborescens)
- Hibiscus (Hibsicus rosa-sinensis)
- Impatiens (Impatiens spp.)
- Iresine (Iresine spp.)
- Lantana (Lantana camara)
- Mandevilla or dipladenia (Mandevilla spp.)
- Nasturtium (Tropaeolum majus)
- Paris daisy (Argyranthemum spp.)
- Pelargonium or geranium (Pelargonium spp.)
- Purple fountain grass (Pennisetum x advena ‘Rubrum’, anciennement P. setaceum ‘Rubrum’
- Pentas (Pentas spp.)
- Petunia (Petunia × atkinsiana)
- Plectranthus (Plectranthus spp.)
- Polka dot plant (Hypoestes phyllostachya)
- Portulaca (Portulaca spp.)
- Salvia or sage (Salvia spp.)
- Scaevola (Scaevola spp.)
- Silver falls (Dichondra argentea)
- Spiderwort (Tradescantia spp.)
- Star of Bethlehem (Solanum jasminoides)
- Streptocarpella (Streptocarpella spp.)
- Sweet alyssum (hybrid) (Lobularia ×)
- Sweet potato vine (Ipomoea batatas)
- Vervain (Verbena × hybrida)