How to plant, grow & care for nemesias

There’s something irresistible about nemesias. Prolific bloomers, these cheery little plants, only about 30cm tall, are covered – and I do mean covered – in sweetly scented flowers for months on end. The colours are fabulous too. Choose from rich magentas and zingy oranges, or go for some of the multi-hued varieties to really dial up the colour contrast in your plot. Take a look at our range of rooted cuttings and young plants – all trialled here at Perch Hill – perfect for beds, borders and containers alike.

Details Where & when to plant How to sow How to plant Care guide Pests, diseases & common issues Frequently asked questions

Details

Calendar

Jan J

Feb F

Mar M

Apr A

May M

Jun J

Jul J

Aug A

Sep S

Oct O

Nov N

Dec D

Sowing

Planting

Flowering

Where & when to plant

Where to plant

Soil type

Most reasonable garden soils will do, so long as they have good drainage.

Aspect & position

Nemesias are native to South Africa and prefer full sun. They make excellent plants for containers.

When to plant

Sow nemesia seeds undercover in March-April, or direct sow in May-June. Plant out seedlings and young plants once the frosts have passed in late May or June.

How to sow

In late March or April, fill divided seed trays or modules with peat-free compost and moisten well. Sow thinly, pushing in seeds to a depth of about 3mm and place in a greenhouse or on a warm windowsill (a temperature of about 20C is ideal), and cover with an empty plastic compost bag or black bin liner to keep out the light and to keep the soil moist.

Check every morning for germination, at which point remove the bag and place the tray in a light, cool place – a propagator in a frost-free green house or a cool windowsill is ideal. Water sparingly.

When you can see roots filling the bottom of the module, pot the seedlings on into 9cm pots, pinching out the growing tips when the plant is about 8cm tall to encourage bushier growth. Plant out after the frosts, hardening the plants off over 1-2 weeks before you do so.

Photography by

Jonathan Buckley

How to plant

We’ve done a bit more of the legwork here for you, so if conditions are right, you can plant these straight into your containers or the garden by following the instructions below. If weather conditions aren’t right (i.e., they are too cold or too wet) then you can pot them on into a 1 or 2 litre pot before planting.

Step 1.

Prepare the ground (ideally at least two weeks before planting) by forking over the soil and incorporating plenty of organic matter such as homemade compost or well-rotted manure. Remove weeds and large stones as you go.

Step 2.

Water your plants well before planting. You can also soak them for 20 minutes in a bucket or wheelbarrow of water if they seem particularly dry.

Step 3.

Rake to level the soil, breaking up any large clumps. Try to create a fine, crumbly soil texture. The young plants roots will like this.

Step 4.

Dig a generous planting hole and, if necessary, incorporate some sand or horticultural grit to aid drainage.

Step 5.

Place the plant in the hole so it sits at the same level as it was in its previous pot and firm the soil around it to anchor it.

Step 6.

Water well, and once it looks like all the water has been absorbed, water again with a really good amount of water (not a sprinkle). Do this every 5-7 days (if there has been no rain) to encourage roots to be drawn down deep into the ground, resulting in stronger plants. Keep well-watered during dry spells, until established.

Step 7.

Remember that plants tend to look better in groups of three, five or seven, and allow about 15-25cm between plants in borders.

Photography by

Jonathan Buckley

Care guide

Watering

Water well until established and in dry periods to promote flowering. Plants growing in pots will need regular watering, watering only when the top two inches of the soil feels dry.

Fertilising

Feed nemesias in containers with a liquid fertiliser every couple of weeks throughout the growing season. There’s no need to feed plants growing in borders.

Pinching out

Pinch out the growing tips of young plants to encourage a bushier habit.

Deadheading

Deadhead to encourage more flowers and, after the initial flush of flowers is over, cut back by at least half to encourage more blooms.

Propagating

From cuttings

Nemesia is easy to grow from cuttings. Between early and mid-summer, choose leafy, flower-free shoots about 15cm in length and snip off the plant. Place in a plastic bag immediately to prevent them drying out.

Fill a container with peat-free potting compost mixed with 50 per cent perlite or grit.

Trim the end of the cutting just below a leaf node so it is about 5-10cm long. Remove the lower leaves above the cut so there is a good stretch of clear stem, and pinch out the soft tip.

Push in the cuttings around the edge of the pot, taking care that they don’t touch each other. The first set of leaves should be just above the compost.

Water well and cover with a clear polythene bag, and move to a warm place out of direct sunlight. Remove the bag for 10-15 minutes twice a week for ventilation.

Monitor to ensure the soil stays moist (but not wet) and after around two to four weeks, gently try to lift a cutting. Any resistance shows that rooting has started. Remove the bag and leave to grow on until strong, healthy roots have formed, when the plants can be potted up individually.

Overwinter in a cool, frost-free environment and plant out in late spring when all risk of frost has passed.

Overwintering

Nemesias are most often grown as annuals, but if you wish to try to overwinter yours, trim lightly before moving undercover to a frost-free place, and cut back hard before planting out again in spring. If you have to leave them outside, protect with horticultural fleece and place somewhere sheltered.

Pests, diseases & common issues

Slugs & snails

Slugs may well eat seedlings and young plants, so put slug barriers in place to deter them.

Deer & rabbits

Deer and rabbits will also eat nemesia so be sure to have protective fencing in place if they are a problem in your area.

Root rot

Root rot occurs when plants are grown in waterlogged soil. It’s best to try to avoid it by incorporating plenty of grit or perlite into soil/your containers to improve drainage, and by not over-watering. It is sometimes possible to treat by removing your plant from its container and removing excess soil. Rinse the roots well and use clean secateurs to cut off any dead or diseased roots. Clean and disinfect the pot and fill with fresh compost mixed with 50 per cent grit. Firm in your plant and then use clean secateurs to reduce the foliage by between 30 and 50 per cent, to avoid stressing the reduced rootball. Water lightly and be careful not to overwater in future.

Why is my nemesia dying

Nemesias need moist, well-drained soil and full sun to thrive, so if your plant is not happy, consider whether it has enough – or too much – water, or if it might need moving to a sunnier spot. Pests such as aphids or diseases such as powdery mildew can also be to blame, or your plants might be lacking in nutrients, particularly if they are in pots. If this is the case, give them a liquid feed.

Why is my nemesia wilting?

Although nemesias like full sun, they can struggle in very hot temperatures, so if you suspect this might be the problem, cut back hard and water well and they’ll soon bounce back. Alternatively, the plant’s roots may be rotting due to overwatering.

Frequently asked questions

How do I pronounce nemesia?

Ne-mee-see-a.
Are nemesia snapdragons?

Nemesia are in the same family as snapdragons. Their common name is Cape Snapdragon, reflecting their South African origins.
How tall do nemesia grow?

Nemesia grow to about 30cm tall
Do nemesia come back every year?

Our nemesias are tender perennials, so they should come back every year if they overwintered in a frost-free place. However, many people prefer to grow them as annuals, replacing them with new plants each spring.
Can you split nemesia plants?

Nemesia caerulea is a woody perennial that can be divided in spring should it get large enough to need it. Annual nemesias should not be divided.
Can you grow nemesia indoors?

Nemesia grow best outdoors in full sun.
Which nemesia are scented?

Many nemesia varieties are scented. Some of our favourites include Nemesia denticulata ‘Confetti’ and the delicate, white N. ‘Wisley Vanilla’.
Does nemesia spread?

Nemesia are good plants for ground cover or for trailing on the top of walls, but they do not spread invasively.
Are nemesia hardy?

No, they must be protected from frost.
Is nemesia poisonous to dogs?

No, nemesia is not poisonous to dogs.
What should i grow with nemesias?

Nemesias look great with other dainty flowers such as diascias, alyssum and verbena. Calibrachoa and the daisy-like flowers of bidens make an excellent contrast.

How to cut and arrange nemesia

Nemesias make excellent cut flowers, especially in small posies and bud vases. Cut first thing in the morning if possible. Dip the stem ends into boiling water for a short five seconds before plunging into a vase filled with cold water. They should last for around a week.

Common name	Nemesia, Cape Snapdragons
Latin name	Nemesia
Type	Annuals or tender perennials grown as annuals
Height	30cm
TLC rating	Easy
Aspect	Full Sun
Planting position	Front of borders, ground cover, containers, hanging baskets
Suitable for pots	Yes
Good for pollinators	Yes
Good for cut flowers	Yes