April, the time for planting is near and with it comes assessment. Gardens change. Trees grow or are removed; the amounts of light and wind are altered. Plants die, or grow so much they subdue and dominate a garden. In nature change is managed by extremes of weather and topography. Storms, ice, fire, snow-melt, flooding and rock slides, grazing'etc. Humans will manage a garden in a similar manner with the objective of improving overall attractiveness of the plantings, or perhaps just to grow some difficult species.
When a garden is fresh and new, the rush to fill it as soon as possible can lead to over-planting, a common practice of the nursery/landscape trade to sell plants and satisfy the urge to make it finished. One can do this in the rock garden with fast-growing mats like veronica liwanensis or v. oltensis. Mildly thuggish, they can be ripped back if spread out of bounds. Some plants can grow in these mats, but I find it rather too competitive for choice plants. Ground cover plants like geranium sanguineum can grow over and eliminate others very easily; and, though it can be dug out, any remaining pieces of root will allow it to re-establish. Choice of plants is critical. Weedy plants, no matter how pretty, carry a price in nuisance.
Conifers and shrubs can also overtake an area. Again the nursery/landscape trades favour grafts on faster-growing root-stocks so that a full-size is available for sale. Specialty nurseries are more likely to use slower-growing root-stalks or propagate from cuttings. When building a new garden, it is quite OK to use some larger shrubs to create a more mature look. We did this in the tufa garden with ~ 30 daphne x 'lawrence crocker'. Years later they occupied too much space and we ripped out 20. The daphnes - knowing that they would have well-developed, fibrous roots, they were put into gallon pots and sent to the sales bench. If transplanting to a new location, the roots can be trimmed to fit the hole or crevice. - overlaying matted roots will die anyway. Backfill with the same soil was removed.
Division works well with alpines that lack a tap root; often the individual rosettes have roots attached - the "Irishman's cuttings". Primula allionii and its hybrids are readily done this way. Avoid the older, corky parts as they can harbour disease. Younger bits will grow faster. Check for the dreaded root aphis - a white, waxy film in the roots about the crown. If found, treat plants with Marathon drenches to eliminate it. Silver saxifrages and androsace can be divided in a similar fashion, spring or fall.
- Generally speaking almost everything can be moved/divided in spring. Plants want to grow then, and new roots are produced freely. Fall (Sept. - Nov.) is also good, but less sure than spring. If the weather is to dry and the plants are stressed, the results are poorer. Some things, e.g, willows and oaks in Eastern NA transplant very poorly in the fall.
- Juno and oncocyclus iris, like many other hardy bulbs, should be planted in the fall only. Even potted specimens are best left alone as even minor root disturbance when in active growth will cause the plant to decline - this I know from bitter experience. By August they are dormant, can be dug and left unattended on a shelf for weeks. Upon replanting, even in late November, they quickly establish new roots and will grow slightly throughout the winter. From December on, I never disturb them. This is why they are offered only from August to October. One can say ditto for Adonis vernalis. Bare root plants in the fall transplant 100%.
- Although most native soils are fertile enough, it does help to put a spoonful of a rock powder such as apatite, greensand or carbonatite with the transplant. We use a carbonatite for all the mixes except for the ericaceous material. It acts as a slow-release fertilizer and will not burn roots. In nature plants that grow in areas that have apatite or carbonatite, exhibit more vigour. What works in nature, works in the garden.
- Before you set about digging in the garden, consider the most basic tool and how over the years it has become increasingly difficult to find good hand tools. Mass marketing and manufacturing have degraded the selection of hand tools that we still depend to carry out simple chores. I have 2 ancient (50 year old) Lawson trowels that are no longer available. I had copies of them made using a tool steel (for blade strength and a thin profile for sharpness). The steel blade is hardened to ~ 54 Rockwell, and the tang is bonze welded to the blade to avoid heat stress. This type of blade is far superior to the usual machine-stamped type which is thicker, softer steel making for a heavy, awkward-feeling tool. The lightness of our trowel makes it feel very lithe in the hand. I modified the profile to better suit use in a rock garden. The blade is firmly attached to a hardwood handle and set with epoxy. The handle is painted red so you won't lose it. It should last 50 years. If you fancy one for yourself or a friend, and look it up in our catalogue, or come to the Stonecrop Sale where you see it for yourself. .
I did a websearch for trowels. Most offerings must be the result of marketing "notion" based on appearance. I did find 2 sites worth looking at:
www.gardenfurnishings.com has high-carbon trowels made by DeWit that are forged in a profile that looks correct. It does have an off-set handle, so it will be a bit more awkward in a tight crevice. It also won't be as comfortable shoved into a back pocket.
www.redpigtools.com is a site for "blacksmith made" tools. There is more variety here, as the production runs are small - many of interest to tool collectors I suspect. There is a "rockery trowel" that is properly narrow with an in-line handle. The blade appears to be thicker than the one we make, but it still looks useable.