Raspberry Care and Pests
There's little to be done for your berry plants during the first year. Cultivate to keep weeds down at least through early summer to let the plants get established, then apply a layer of mulch thick enough to smother weeds - 4 to 8 inches deep. Mulches rich in nutrients produce superior-tasting fruit. Composted leaves around the plants, supplemented with manure, are a good choice. Besides mulch, moisture is the critical ingredient throughout the life of your raspberry patch. For plenty of plump, juicy berries, trickle irrigation of some kind - perhaps a soaker hose under the mulch - is ideal. Short of that luxury, at least ensure I inch of water per week, more during dry spells.
Second Year Maintenance
By the second year you will have to work at keeping the canes within the 1- or 2-foot-wide hedgerow boundaries if you planted a variety that spreads through root suckers. Periodically dig up any stray canes and transplant or destroy them, or just run a tiller alongside the rows. Beyond that, put off any substantial pruning until the third year.
Supporting Your Berries
A year or two after planting you will know whether or not your canes need support. All black and most purple raspberry plants can be individually staked, but this is obviously impractical for reds, yellows, and those purples with a propensity for spreading underground. For those types, a T-trellis system works nicely. Certain varieties are more upright than others; you may not need to support them at all. Just grow them, see how droopy they are, then decide if you need to put up a T-trellis afterward. You don't have to tie the canes; they'll just grow up and rest against the wires. Besides producing a tidier berry patch, trellising makes for cleaner fruit, less breakage, and easier pruning and harvesting.
Raspberries are bothered by insects and disease less often than most other fruits. Nevertheless, the risk is there. In most cases, you can avoid sprays by practicing careful garden sanitation and removing wild plants nearby. Two insects in particular may be attracted to your raspberry patch. The cane borer makes itself known by a sudden wilting near the tops of new canes, where the adult beetle lays its eggs. If undisturbed, the larvae will travel down the cane, kill it, and infect others. Look for a slight swelling and two rings on the cane that pinpoint the borer, cut off the cane just below the lower ring, and burn it. To stay ahead of the borers, remove affected canes as soon as you notice them.
The tarnished plant bug, which feeds on young berries and flowers, is less easily controlled. Ideally, you should situate your raspberry patch away from hay or corn fields where the bugs breed. If you're not getting fully developed fruit, you may have to resort to more direct methods of control, possibly pesticides.
Raspberries may also fall prey to several fungal diseases (anthracnose, cane and spur blights, orange rust [black raspberries only], and verticillium wilt), bacterial diseases (crown and cane gall), viruses (mosaic, leaf curl, and ringspot), mildews, and fruit rot. Good sanitation keeps control many of these diseases.