Using Alpine troughs for decks and patios

Photo by Judith Rogers Alpine troughs are great outdoor containers made of simulated stone, which create miniature scree gardens planted with alpines and succulents.

The larger ones, like any container, are great for patios and decks and the smaller ones can be moved anywhere as a portable garden. Choose the site carefully for large troughs, as once they’re filled with soil, plants and mulch they become much too heavy to move.

A specific mixture of Portland cement, builder’s sand (sand that contains stone particles, not what you would use in a sand box), peat moss, perlite and vermiculite called hypertufa will produce a trough lighter than concrete that can also be left out over winter. The soil for a trough is made from two parts triple mix to one part builder’s sand, with additional grit if desired. This allows for a rich growing medium that has the necessary good drainage. Mimic a small mountainous area in nature by making a mound in the trough with the planting mix and inserting a large porous rock or two partially buried, or try a few pieces of flat rock on their side protruding from the soil. When the planting is completed, mulch the top with pea gravel or grit, which complements the overall stone appearance of the trough.

If constructing a hypertufa trough or purchasing it ready made, look for one with a drainage hole in the bottom, which will help with overflow from heavy rain.

The plants will get enough nourishment from the soil the first year, but after that bury a couple of grains of a 14-14-14 plant food like Osmocote in the soil, beside each plant in the spring. The idea is to keep the miniature plants healthy yet slow growing.

Depending on plant choices, a trough can be filled for full sun or a shady location. Many regular plant species have alpine cousins; the herb thyme can be bought in size varieties as ‘minus’, ‘minor’ and ‘minimum’. There are many types and flower colours of saxifrage, small grasses like carex that can grow as petite as five centimetres tall by seven wide, a mini Yucca, candy tuft, primulas, mini heucheras and very tiny hens and chicks. Alpine troughs can be as plain or intricate as desired; some people prefer to use coloured stones for the mulch, while others plant theirs on a flat plane. These containers present the perfect opportunity to try plants that may not survive in the garden, as the soil can be manipulated to best serve those chosen.

Troughs add interest when placed by a pond — grouping several together provides a diverse collection of mini gardens to enjoy.

Visit my website at http://lavendercottagegardening. blogspot.com.