Rock Garden TIps – Care Calendar for Alpine Garden Plants
You cannot build a rock garden or allied sites and then conveniently leave them to maintain themselves. Therefore, the following information will guide you in dividing the time to enable the various aspects of construction and maintenance to be carried out. The least amount of routine garden maintenance will need to be done in winter, when it is cold, so that is the best time to begin the construction of any site and to carry out the heaviest work. The busiest time is spring, when construction is being completed and planting, mowing and the routine garden tasks are carried out, reaching a height of activity around Easter. So plan and prepare shortly after the spring for the following autumn. Alpine nurseries can be visited at any time of year but you will probably have more free time in the summer.
Construction work on all sites can begin this month, weather permitting. Avoid heavy work immediately after hard frosts, or after rain or snow when the ground is very soft; it is much better to wait until it dries out. In frosty weather large stones can be easily moved over hard ground and placed near the site, even though they cannot be laid. After frosts check that glass covers over the plants have not been dislodged from the wires, and that the wires are still securely in the ground. Make sure that the labels are still firmly fixed and legible. Remove any dead leaves from all sites and cut dead branches from shrubs with sharp secateurs. Most alpine seeds are sent out from mid-winter onwards and should be sown as soon as possible after they arrive. Take cuttings from the fleshy rooted plants. Plants which can be propagated this way are: Anchusus, Armerias, Codonopsis, Convolvulus, Dicentms, Erodiums, Eryngiums, Euphoribias, Gemniums, Lewisias, Morisiczs, Pupzzvers, Platycodtms and Verbuscums.
Construction can continue at a greater pace this month. On warmer days start weeding-a little and often rather than occasional long stretches. Try to weed before the plants go to seed, especially between bulbs. As long as the weather is not too wet or frosty, apply pre-emergence weedkillers from this month onwards. Use simazine combined with paraquat for annual weeds. Follow the manufacturer’s instructions exactly and apply using a bottle sprayer with a guard on. Do not use weedkillers when it is windy and only spray paths and paved areas where you are certain there are no wanted plants. Check labels and glass covers again, as in January. Continuedead wood from shrubs and sowing seeds. Some seeds will start to germinate this month. Prick them out into seed trays and pot up seedlings. Labelled crevice plants can be sown.
Construction should be reaching a climax now and spring planting started if the weather is suitable. Always label as you plant. Continue weeding and, using a handfork, break up thegently round the plants, firming any plants which have been lifted by the frost. Where glass is covering plants check that it is still necessary, i.e. when the weather is cold and damp most of the time. Remove it from plants in growth and store it, cleaned, until next winter.
Cut back all old herbaceous material which died down the previous autumn to ground level; pruneto within 5cm (2 inches) of soil. Feed the soil in shady areas with a mulch of fine forest bark, leafmould, hops or well-rotted . In exposed areas spread it about 3cm (1 inch) thick every third year. All areas will benefit from an annual feed of bonemeal at the rate of 35g per square metre (1oz per sq yd), which can be applied this month. Top dress any sunken parts of the garden with the same mixture used when they were first planted.
Make a plan of plants in each area, plotting them precisely where possible and noting all those that die down to nothing during winter (plants hidden underground as bulbs and other storage organs). Keep grass edges round lawns trimmed.
Pricking out and potting up should be in full swing as seedlings germinate and grow rapidly.
Complete propagation by division since growth is starting now. Divide herbaceous plants and those with multiple stems, from ground level.
A very busy month. Construction and spring planting should be completed this month now that growth is in earnest. Some plants such as Codonopsis will still be dormant. Continue to weed and hand fork the ground each month. Complete the feeding, mulching and top dressing of the soil.
Remove all remaining glass covers. It may be necessary to shade glass or plastic propagation frames in warmer parts of the country, if the weather is warm and sunny during at least part of the day.
Seedlings and root cuttings which show top growth, should be pricked out and potted up. Continue to do this throughout the spring and summer.
Layering of plants for replacement should be done this month. If you pot a few more seedlings than you need yourself, they can be exchanged with friends or given away. Trim lawn edges each week from now until September-October, and fork out any creeping grasses and weeds that appear around the sites.
The propagation frames will need more shading. Covers should be used on all bright days and removed on dull days and when natural shading is cast.
It may be necessary to start watering areas other than sinks, if the top 8cm (3 inches) of soil dries out. Water thoroughly, then leave for as long as possible.
Start collecting ripened seed of alpines and store in dry envelopes or cartons in the shade.
In late May plant out annual alpines and seedlings potted up earlier in the year. Label carefully.
Spray against aphids (green, black or grey fly) as soon as they are seen and continue throughout the summer, repeating the procedure every ten days, using one of the various proprietary products available. Aphids carry dangerous virus diseases, so their immediate reduction is vital.
As the large trailing plants, such as Aubrieta, Helianthemum, finish flowering, cut them hard back removing previous year’s growth, to encourage plenty ofnext year. Also cut back those plants which are stronger than they appeared earlier in the year, to prevent them invading other plants, by removing individual branches. Remember: pruning makes for strong growth.
Regular watering may be necessary by now. Try to do it in the evenings when the weather is cooler, so that the water lasts longer around the plants.
There is more seed to collect now. Take nodal and heel cuttings off many alpines this month, as growth is firming up but not yet hard.
Continue watering unless storms make it unnecessary.
Seed collecting is now at its height and should continue until September. Clean seeds in preparation for sowing.
Take more cuttings as in June. Prune trailing plants after flowering to keep growth bushy.
By now bulbs will have died down and alpine lawns can have their first mowing and trimming.
Have a look at alpine nurseries and gardens during the summer holiday months.
Continue to trim back and prune after trailing plants have flowered. Watering may not be needed.
Plant alpine bulbs.
Take heel cuttings from the more woody alpines, but not conifers.
Weekly mowing of alpine lawns can now be merged with other mowing.
Begin to construct and plant rock gardens,, pavements, sink gardens and screes.
Shades on propagating frames are only needed during the warmest part of the day when the sun is out.
Take conifer and Aubrieta cuttings. Water only when necessary.
Plant alpine bulbs.
Update the plan in case labels disappear during winter.
Construction, with crevice planting only; on any site. Good month for making reproduction sinks i.e. any container other than a true stone sink. Label and list all crevice plants.
Take shading off propagating frames until next April.
Order seed lists (if not already done). Take conifer and Aubrieta cuttings. Remove fallen leaves weekly now.
Construction can take place on all sites; another good month for sinks. Crevice planting only. List all plants on the plan after labelling. Check that glass covers are firm.
Remove leaves off all alpine areas as they fall, leaving the stems and leaves of herbaceous plants exposed until next year.
Divide herbaceous plants.
Construction can take place with crevice planting on all sites. This is also a good month for reproduction sinks. Label and list as planting is carried out. Check that glass covers are firm.
Remove leaves and fallen branches.