Dry pots Watch out for dry pots within a block. Automatic irrigation systems are notorious for being uneven in distribution if unchecked. Putting crops with different compost types on the same area, crops of different size or bulk can also result in some being overwatered and others underwatered. The best method I know is to check the weight of pots.
Yellow foliage Cytisus, Potentilla and Ceanothus often show foliage yellowing as the new leaves emerge. While this is an iron deficiency, it is also due to root development not keeping pace with foliage development at the start of the season. Water the compost with an iron chelate EDDHA at the rate of 100g/10 litres diluted at 1:200. This one-off application is more effective than repeated foliar applications of EDTA chelates. Keep your feeding programmes on bedding and overwintered herbaceous plants going. If you reduce watering in dull weather, use every opportunity to maintain liquid feeding when possible.
Liverwort Clean up liverwort infestations on container beds with applications of Mogeton, including the pathways. Follow that up after a few days with Jet 5 to finally clean up the bed before putting your good, clean, newly potted plants down. On really heavily soiled groundcover beds, it might be worth power-washing them to remove all of the unwanted growth and then spray with Jet 5, which is more effective than just brushing.
Weed seedlings Consider the use of Betanal Flow to control the seedling weeds that have emerged in field crops of trees and roses after your herbicide application. The rate of application is dependent on the air temperature at the time of application. Use one-third rate in lower temperatures and one-quarter rate for hotter periods. If you are unsure, it is best to do two applications at one-quarter rate, seven days apart, then one at one-third rate to control the larger weeds among the crop. Avoid spraying if there is frost predicted for the night after application or you may get crop damage.
Leaf spots Check now for leaf-spot development particularly if you have had some warm weather. Inspect Viburnum, Ceanothus and Clematis closely and spray with Amistar (2009-0443), Bravo 500, Cercobin WG (2008-1384), Rovral WG, Scotts Octave, Serenade ASO (2009-0246), Signum (2004-1673) or Switch before the end of the month.