Gardening – Adding garden colour

We have several old concrete laundry tubs that are planted up with Alstroemeria, also known as Inca or Peruvian lilies, which have put on a beautiful show for several years from spring through summer and even some flowering into autumn. Each tub is planted with a different colour including red, orange, yellow, purple, salmon, pink and white.

All are the old-fashioned florist Alstroemeria, which we prefer growing rather than the newer, dwarf varieties that are found in every garden centre these days. The dwarf varieties are less messy, as the stems don’t get blown over by the wind and they are less invasive. We prefer the taller varieties, for the simple reason that they make a glorious and long-lasting cut flower. We’ve acquired most of these from friends, relatives, TradeMe and the occasional find at a Farmers Market, as it is difficult to buy these older varieties from garden centres.

We grow them in concrete tubs because, left to their own devices, these are very vigorous plants that like to spread and can easily take over a garden bed in a short time, with the deep-rooted rhizomes being quite hard to dig out. Concrete is chosen, partly because the rhizomes will eventually split most plastic pots, but also the rhizomes are very temperature sensitive, preferring a cool root run, which plastic pots are less able to provide. If concrete tubs are not available to plant in, then terracotta pots can be used.

Rhizomes are planted about a hand-depth deep, spreading out the storage roots below this level. This depth provides a cooler environment than a shallower planting. Planting this deep does increase the risk of waterlogging in our climate and soil types, and if the soil is not freely drained, rhizomes or the root system will quickly rot, which is another good reason for growing in tubs.

Alstroemeria produce their best display if grown in full sun, although they will still flower reasonably well in dappled shade. In windy spots, the tall florist varieties may need staking or netting to keep the stems upright. Regular watering is important over the drier months. Alstroemeria are known as gross feeders, not because they are messy eaters but rather that they require reasonably high inputs of fertiliser to maintain flower production. A regular application of a fertiliser similar to tomato or rose fertiliser is ideal.
Picking the flower stems by pulling rather than cutting is recommended, as this encourages more stems to develop. For the same reason, pulling a third or so of the vegetative stems can encourage more flower stems and any spent stems that were not picked for the vase can be pulled also. Before placing in a vase, cut off the white part of the stem, as this will help water uptake and keep the flowers fresher for longer.

Once planted, a well-managed crop of Alstroemeria can be expected to remain productive for three to four years. Lifting the rhizomes can be done from early autumn through to early spring; if there are still stems on the crop these can be cut back to 10-15cm above ground level about one week before lifting, after this the rhizomes are lifted, divided and replanted.

Aside from slugs and snails, or rhizomes rotting due to waterlogging, these are very tough and adaptable plants that reward the gardener with a bounty of beautiful flowers every year. Well worth growing!