A WORD of caution to start off – I know it’s mid-May but you know the old saying about ‘ne’er cast a cloot til May be oot’ which is generally translated as not to fling your vest off until the end of May. The same applies to the garden but not in the vest-area, obviously. The fact is that we can still be caught out by cold snaps and it is not unknown to have a sharp frost in what is considered to be late spring/early summer.

By now, you will have put out your various veg plants and things like sweet peas, morning glories, thunbergia (black-eyed Susan) so keep an eye on the forecast and reach for the fleece if necessary.

If you have put your hanging baskets out as well, then the same applies, only here, take them down and put somewhere frost free overnight. They can also be damaged by high winds so again, take them down until the danger is passed.

On to marigolds and a bit of an explanation. There are many different species of marigold but only a few of garden worthiness. These fall into four categories and it is these that I’m going to explain.

Firstly, the French Marigold – those little ones that you buy in bedding packs and which are used in greenhouses to protect crops from whitefly. These are forms of tagetes patula and are a distinct group.

Secondly, African marigolds (which incidentally, do not come from Africa at all!). These are forms of tagetes erecta and again, you will see them in bedding packs. They are larger than the French version and have much bigger, multi-petalled, round heads.

Then, a strange one here, that you will not see being sold as a plant in any garden centre. The Mexican marigold, tagetes minima, is not a pretty thing but it is able to do an amazing job at weed control, in that it exudes toxins that actually reduce or even kill the spread of such nasties as bindweed, couch grass and ground elder. It is grown from direct sowing of the seed but if left to its own devices, can become a bit of a thug in its own right. Sarah Raven has trialled this at her garden in Perch Hill with good results.

Finally, English Marigolds – these are NOT tagetes, but calendula. They make brilliant plants to encourage friendly wildlife critters into your garden or allotment. The single-flowered ones are the best for this and not only do they add some zing to your planting, they are also edible! These are the types that calendula cream is made from, which is brilliant for mild skin disruptions. They are easy to grow from seed so great for the kids to try as they germinate quickly as well.

The clematis planting season is on us in earnest. You will see when you buy them that they come in quite long pots. When you plant them, bury them deep in the soil as they need a good root-run; this will also help to protect against the ravages of clematis wilt, a fungal disease that can strike without warning, killing off the whole of the top growth but hopefully not the well-buried roots. Clematis also like their feet in cool shade so if you are planting in a sunny spot, make sure to mulch well. Gravel or stones make a good mulch for them as they reflect heat. If planting against a wall, make the planting hole about 12-18in away if possible and lean the plant back towards the wall – that way it stands more chance of getting enough water.