‘Naturalizing’ plants that grow like crazy in Southern California gardens

1-naturalizingIt does not make sense that a fancy tropical plant grows with weedy abandon despite droughtlike conditions, but the botanical world is full of surprises and spring-blooming amaryllis is one of them.Amaryllis is that gift plant, often packaged in a tall box, you see growing out of a huge bulb with gigantic trumpet flowers to match. Flowers may be scarlet or red-orange, solid colored or with white markings, or white flushed with pink.

What you may not know is that, planted in the garden, spring-blooming amaryllis will slowly expand its presence. Amaryllis is a paradigmatic example of a species that naturalizes in the garden.

Naturalization refers to a phenomenon whereby a plant takes over an area of ground either by asexual reproduction of its bulbs, rhizomes, tubers or corms, or by its aptitude for self-sowing or germinating its seeds in place, without human assistance.

Naturalizing plants include daffodil (Narcissus spp.), daylily (Hemerocallis spp.), lily of the Nile (Agapanthus spp.), flag iris (Iris germanica), canna lily (Canna spp.), calla lily (Zantedeschia aethiopica), Peruvian lily (Alstroemeria spp.), hellebore (Helleborus spp.), love-in-a-mist (Nigella damascena), California poppy (Eschscholzia californica), bachelor’s button (Centaurea cyanus), blanket flower (Gaillardia spp.), valerian (Centranthus ruber), pot marigold (Calendula officinalis), nasturtium (Tropaeolum majus) and larkspur (Consolida ajacis).

Here, we are not talking about invasive plants in the style of ground covers such as ivy that overwhelm you. Based on my experience, all of the above naturalizers are ultimately noninvasive and easily kept under control, if that is your wish, through hand pulling or shallow digging with a shovel.

The amaryllis beauties you see blooming this time of the year are native to Central and South American rain forests. Yet they can obviously adapt to dry conditions. This past rainy season has been one of the driest ever recorded in Los Angeles, yet a large planting of amaryllis growing in dry soil, on Magnolia Boulevard in Valley Village, between Bellaire and Bluebell avenues, shows no signs of stress, with hundreds of flowers on display.

Amaryllis is the ideal candidate for narrow courtyard planters. Amaryllis grows equally well in full- to half-day sun exposures, and can even accept some shade. Amaryllis is not affected by adjacent concrete or asphalt and will perform without difficulty when situated next to patios, pool decks or driveways.

It is important to distinguish between spring-blooming amaryllis (Hippeastrum species) and summer-blooming amaryllis, commonly called naked lady (Amaryllis belladonna). Spring-blooming amaryllis flowers are scarlet, orange or white, either solid colored, striped or blended. Naked ladies, on the other hand, are exclusively pink. They owe their name to the fact that their flowers appear naked on the stem without the benefit of surrounding foliage, which develops some time later, following emergence of their flowers.

Nearly three years ago, I saw a tiny seedling with grayish, felt-textured leaves sprouting next to my front walkway. Just this spring, that seedling reached a height of 8 feet with a 2-inch diameter trunk. It is known as pride of Madeira (Echium candicans) and has bloomed for the first time, sporting fat, foot-long flower candles covered with bluish purple florets. Pride of Madeira is native to Madeira Island, off the coast of Portugal, and to the Canary Islands, off the northwest coast of Africa.

Summer irrigation is the enemy of pride of Madeira and hastens its demise. If you just let this plant grow and never water it, it will persist for a decade or more. It drops viable seeds so you should see more of the same once you have planted one. Keep in mind that seedlings are like children; each one is different and may not be as attractive as its mother plant. If you want an exact replica of your pride of Madeira specimen, you will have to do root cuttings, a task that is easy to perform. In spring or fall or, for that matter, at almost any time of the year, take 4-inch to 6-inch shoot tip cuttings and stick them in well-drained soil, whether in the garden or in pots. A recommended soil mix for cuttings contains 50 percent sand or perlite and 50 percent peat moss.

Pride of Madeira is as strong a magnet for bees as I have seen. It would make sense to plant several of these plants in the middle of an orchard or vegetable garden. When you increase the population of bees, you increase pollination, resulting in increased crops of fruits and vegetables.

Speaking of plants that thrive on neglect, such as amaryllis and pride of Madeira, I highly recommend vining asparagus fern (Asparagus setaceus). Florists are well acquainted with this plant since it is used as a soft and lacy filler for bouquets and vase arrangements. In the garden, it is highly attractive when allowed to wind its way up a trellis, arbor or wrought-iron fence. The downside of this vining asparagus is its thorns, so make sure to wear gloves when pruning it. Once it starts to grow, there is no stopping it and, although it grows most densely in the sun, it can also tolerate some shade. It is also used in containers as both a patio and indoor plant.

Tip of the Week

This is the moment that Martha Washington geraniums (Pelargonium x domesticum) are looking their best. I see masses of their pink to red to purple flowers on hefty shrubs that reach four feet high and three feet wide. Leaves are finely cut around the edges, adding to the handsome visage of this woody perennial. They appreciate full sun and do equally well whether planted in pots or in the garden.

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