Growing Guidelines

 

Planting dates

Plant after the risk of frost is over, usually mid to late May. If you receive your plants early in the season, it is best to grow them on in a greenhouse, conservatory or a sunny windowsill until the danger of frost has passed. You can plant them out before this date but a late frost may kill off the above-ground shoots of a newly planted plant. If this does happen the plant will regrow but you will have lost the advantage of getting you plants early.

Planting is not recommended after September as the plants will not have time to establish before the first hard frosts. (See later paragraph on hardiness).

 

Choosing a planting position

Alstroemeria are not very fussy about planting site. The only real problem is a dark site prone to waterlogged soil so avoid this. Ideally choose a spot sheltered from the wind with full sun or light shade. The taller standard varieties will grow to an average height of 60-90 cm so position them towards the back of a border and in most cases they will need staking. Modern hybrid alstroemeria require minimal maintenance and are not invasive. Unlike older varieties they will simply form a clump gradually increasing in size each year. If a group of Alstroemeria is being planted space each plant 60 cm apart.

 

Soil

Alstroemeria will thrive in most conditions so long as the soil is well drained. Heavy soil will need improvement with compost, well rotted manure or even gravel. A very sandy soil will need repeated watering in the first summer and will benefit from the addition of organic matter. Alstroemeria can be grown in a pot – a size 40 cm diameter would be fine. Use a good quality peat based compost or John Innes No.2, and feed once per week with a general liquid feed once the first flower buds form.

 

Planting

Dig the planting area well to a depth of about 20 cm adding 60-125 grams per square metre of organic fertiliser. Before planting, water the plant well in its pot. Plant with the compost level about 5 cm below soil level, firm in and water. Remember to continue watering regularly if planting during a dry spell. Mulching with 5 cm of compost is a good idea as this will help to retain moisture and keep the rhizome cool in summer (warm, dry conditions at root level will lead to a reduction in flowering). Thereafter, each spring feed with a handful of general fertiliser per plant.

 

Hardiness and over wintering

Alstroemeria are hardy perennials and will survive frosts of –5oC.  However the most common time to lose a plant is during the first winter when the plant will not have established a deep root system. In recent winters waterlogging has probably caused more winter plant failures than low temperatures, so ensure the area or pot has good drainage. Having cut back the old growth to ground level in November cover the plant with 5-10 cm depth of a suitable mulch such as garden compost, peat or well rotted manure. The area covered should be 45 cm across. If the plant is growing in a pot bring the pot into a greenhouse or conservatory for the winter. Alternatively, plunge pot into the border and cover as for a plant growing in the soil.

 

Growing in a greenhouse

(Standard varieties). Plant 75 cm apart. Stake the plants or support with 2 or 3 nets as they will grow taller than in the garden – to about 1.6 metres high. During the summer water well, keep the greenhouse shaded and use maximum ventilation. If the soil dries out or the soil temperature rises above 20 degrees centigrade for more than a few days, under these conditions flowering will slow down or cease. A good mulch of bark chips or well rotted manure applied after watering will help keep the soil moist and cool. Thin the stems once a month by pulling out any weak stems or those which have reached a height of 90 cm without forming a bud. Feed the plants whilst flower buds are present using a liquid tomato food at the concentration recommended for tomatoes.

 

Pests and diseases

Alstroemeria are rarely troubled by aphids (greenfly) or other sap-sucking insects. The young shoots are susceptible to slug damage in the spring so use slug traps near them.Click Here to go to the Pests and Diseases page for further details

 

Additional information