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Cosmos bipinnatus 'Rosetta'

Mexican Aster

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Cosmos bipinnatus 'Rosetta'

Mexican Aster

Availability: Out of stock

Packet Size:500mg
Average Seed Count:50 Seeds


'Rosetta’ is an outstanding new variety of Cosmos that has earned the Fleuroselect Award for colour pattern, flower size and shape. Subtle, delicately striped blooms in romantic shades of blush pink and rose, some with an inner collarette of smaller fluffy petals, over light airy foliage.

Cosmos 'Rosetta' grows to a height of around 75 to 90cm (30 to 36in) with a spread of 35 to 50cm (14 to 20in) spread. It is short enough to be used at the front of the border and can be used in larger container planting.
By late summer the bushy plants form a beautiful rounded clump with rich green lacy foliage. Long and free-flowering this splendid variety is gorgeous in flower beds and borders it also works well as a summertime cut flower.

Cosmos are very easy to grow from seed and are unrivaled as long-standing performers in a garden. They are the perfect choice for children or the armchair gardener. Disease free, heat and pest-resistant they thrive on neglect and are able to withstand drought and survive harsh conditions in urban gardens and wildflower plantings. Deserving a sunny site in any garden, these adaptable plants are great for cutting, pots and borders.

  • Awarded the Fleuroselect Approved Novelty Award
    Fleuroselect, the international organisation for the ornamental plants industry have awarded Cosmos bipinnatus 'Rosetta' the Fleuroselect Industry Approved Award. This early and floriferous variety provides a wonderful colour pattern, flower shape and flower size.

Sowing: Sow indoors March to April, or sow outdoors April to May
Sow indoors in early spring 3 to 4 weeks before planting outside, alternatively, the seed can also be sown directly where they are to flower in mid to late spring. Keep soil moderately moist during germination.

Sowing Indoors:
Use well drained soil and cover to a depth of 3mm (1/8in). When large enough to handle, transplant the seedlings into small pots to grow on. Acclimatise to outdoor conditions for 10 to 15 days before planting out after all risk of frost 15cm (6in) apart.

Sowing Direct:
Prepare the ground well and rake to a fine tilth. If sowing more than one annual in the same bed, mark the sowing areas with a ring of sand and label. Sow 1mm (1/18th in) deep in rows 30cm (12in) apart.
Sow seed sparingly or they will choke out other seedlings.
The seedlings will appear in rows approx 6 to 8 weeks after planting and can be easily told from nearby weed seedlings. Thin the seedlings out so they are finally 30cm (12in) apart. Carefully replant thinned plants.

When the seedlings have three pairs of leaves, pinch out the tips, leaving at least one pair of leaves.
Only water in an extended drought and do not apply large doses of fertiliser as flowering will be suppressed.
Stake the taller varieties with a single or tripod of canes and some twine. Cosmos foliage is finely-cut into threadlike segments. When flowering, the taller varieties may become top heavy. This problem is alleviated when grown in groups, as the bi-pinnate leaves interlock, and the colony supports itself.
Deadhead to prolong flowering and encourage new flower buds. At the season's end, don't be too quick to pull up withering cosmos plants. Birds (particularly gold finches) love to snack on their seedheads in autumn, and the seeds that they miss may drop to the ground and reward you the next year by sprouting into a whole new crop.

Cut Flowers:
Cosmos is a cut-and-come-again bloomer, meaning that the sooner you cut the blooms, the quicker new buds will pop up to replace them. The blooms appear so profusely that you'll still have plenty of colour in the garden after you've picked your flowers. If you sear the stem end in boiling water for twenty seconds they will last a week in water.

Plant Uses:
Cottage/Informal Gardens, Flowers Borders and Beds. Container Planting.

When Spanish explorers were looking for riches in Mexico to send back to Spain, one of the treasures they found was the golden cosmos flower, Cosmos sulphureus.
In 1789 the flower made its way to England with the wife of the Spanish ambassador to Spain. Half a century lapsed before the golden cosmos reached the US indirectly from England and Spain and directly via Mexico.
Horticulturists are always trying to improve on Mother Nature and today many cultivars of Cosmos sulphureus are available. Depending on variety they will grow anywhere from 30cm to 200cm (1 to 7ft) in height.

Cosmos have been reassuring gardeners ever since the 1930s, when breeders first coaxed cosmos to bloom earlier than the native Mexican species, the flower-growing public has been hooked.
Like many of our warm weather annuals such as marigolds, Cosmos originated in Mexico and South America. Spanish priests grew cosmos in their mission gardens in Mexico. The evenly placed petals led them to christen the flower Cosmos, derived from the Greek kosmos, the word for harmony or ordered, or balanced universe. From this we also get the common name of 'The Mexican Aster'.
The species name is from the Latin bipinnatus meaning 'twice-pinnate' The botanical epithet is from the Latin pinnatus meaning 'with leaflets arranged in opposite pairs'.

Rosetta or Rosette meaning 'little rose' in Italian and French respectively, was the name of a port city of the Nile Delta, located 65 km (40 mi) east of Alexandria in Egypt. The name was used by the French at the time of Napoleon Bonaparte's campaign in Egypt and thus became eponymous of the Rosetta Stone, which was found by French soldiers at the nearby Fort Julien.
In 1799, French soldiers were building a fort near the Egyptian village of Rosetta. The soldiers unearthed a dark grey-pinkish granite stone that stands about four feet tall and two and a half feet wide.
Inscribed with three versions of a decree issued at Memphis, Egypt in 196 BC. The top and middle texts are in Ancient Egyptian using hieroglyphic script and demotic script while the bottom is in Ancient Greek. As there are only minor differences between the three versions, the Rosetta Stone proved to be the key to deciphering Egyptian hieroglyphs.

Additional Information

Additional Information

Packet Size 500mg
Average Seed Count 50 Seeds
Family Asteraceae
Genus Cosmea, Cosmos
Species bipinnatus
Cultivar Rosetta
Synonym Cosmea bipinnata
Common Name Mexican Aster
Hardiness Half Hardy Annual
Flowers Subtle, delicately striped blooms in romantic shades of blush pink and rose
Natural Flower Time May to August
Height 75 to 90cm (30 to 36in)
Spread 45cm (18in)
Position Needs full sun to flourish
Soil Lean, well drained, sandy soils.
Time to Sow Sow indoors March to April, or sow outdoors April to May
Germination 7 to 10 days at 20 to 30°C (68 to 86°F)

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