November 13, 2009 In the Garden

  • We are starting to dry out already. Keep a close eye on container plants. If they are showing signs of stress, it is likely they are either badly root bound (should have been potted on when we told you in winter), hungry or dried out. To get water back into dehydrated plants, a squirt of dishwashing detergent or surfactant will help absorption. However, ignore any advice given elsewhere to add water holding crystals (also called Crystal Rain) to potting mix for anything other than annuals. In our climate with high rainfall, woody plants and perennials will rot out in winter if you add these crystals, however tempting it may be in summer to use them. Partially burying pots and containers into the garden (called plunging) can reduce excessive drying out. It also stops pots with taller plants from blowing over in the wind.
  • It is late in the season for planting out woody trees and shrubs, especially if they are large or root bound. Our advice is to heel them into the vegetable garden until autumn. If you are determined to plant into other garden positions, make sure that the root ball is soaked right through. A watering can just will not do. It can take hours (or leave overnight) to get the water into the middle if it is very dry. Once planted, mulch to conserve moisture and keep an eye on the plant until Christmas at least to ensure that it has not dried out again.
  • If you spray for thrips on rhododendrons (the leaf sucking critters which cause silver leaves), get the first application on when you see the insects on the under side of the new growth. We are not keen on this practice and will only spray one or two special plants ourselves. We would be much happier to hear of gardeners opening up around the plant to encourage air movement, feeding and mulching to encourage more health and vigour and taking out plants which are particularly susceptible to replace with healthier selections. We have drawn a line under many of the cold loving German and American hybrids here and said that we just can not grow them well in our mild, coastal conditions.
  • It is the optimum time for planting kumara runners. This is one plant which really loves warm, light soils.
  • As soon as we get more rain, fungi are likely to attack potatoes and tomatoes. A copper spray applied as soon as the foliage has dried out after rain is usually necessary if you wish to guarantee a harvest later.
  • Brassicas will be under siege shortly, if not already, from much of the insect population and in particular the dreaded cabbage white. This is the single biggest reason for not growing brassicas for summer harvest in our climate. If you don’t wish to spray with an insecticide, you have to start getting creative with old net curtains and the likes. However, this only stops the cabbage white laying more eggs and does nothing to deal to existing caterpillars in residence. We will be eating our remaining brassicas soon and not replanting until autumn, with the exception of brussel sprouts which are best sown in the summer for harvest next winter.
  • Leeks can be sown now.