Garden Notes for September 2025.

Writing just at the start of the month it is good to have rain at last, hopefully the weather will go back to being predictably normal for the rest of the year.

With the nights drawing in and the temperature cooling, there may well be a danger of moulds appearing in many of the bedding plants, especially begonias.  Dead flowers left to rot act as a centre of infection, so keep deadheading.

Daffodils, but not tulips, should be planted up in September.  Try putting some bulbs in a bed especially for cutting in the spring.  Tulip bulbs should be planted in October or even a bit later depending on the variety.

Complete the planting of strawberries in September; otherwise they will not have enough time to establish themselves to build up strong fruiting crowns for next year.  You can plant them in late autumn or spring but if you want good plants, these later planted ones should not be allowed to fruit in their first season.

When picking apples or pears, don’t wrench them off the branch.  Gently push upwards and twist.  If the fruit is ready for picking it will come away easily, if not – leave it for a couple more days.

Continue disbudding chrysanthemums to leave one bud per stem, otherwise let them go to make a spray of much smaller blooms.  Don’t forget to get them in under some protection before the first frosts start.

Ripen off onions and store them when they are completely dry.  Harvest potatoes and keep them in a light proof bag, under cover.

September is the best time to take cuttings of penstemons.  The cuttings should be taken from young, non-flowering shoots as these will root readily in a sandy soil kept in a frame.

Spring cabbage should be planted out now.  It is important to remember to firm well round each plant after planting.  Lettuce can be planted for later cutting.  Good varieties include ‘All the Year Round’ and ‘Winter Density’.

Keep an eye out for tomato blight, and remove any infected leaves.  Towards the end of the month it will be best to clear away the remaining tomatoes as they will not do much more, and the space in the greenhouse will be needed for autumn and winter flowers.

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