Gardeners’ blog – April

April is the perfect time for us to pot on our orchids in the Subtropical House Orchid Case. We will be potting them up in pots of sterilised pine bark, bought from a reputable supplier, to ensure it is sustainable and weed free. We use bark for the exotic orchids as most are epiphytic, meaning they grow on tree branches for support.

Jobs in the nursery during April include staking the pots of elegant, flame-like, lily flowered tulips, which were planted in October and overwintered in a dark cold frame for the winter. These will be placed in the Mediterranean House display with stocks, wallflowers and Schizanthus. Schizanthus are commonly known as ‘poor man’s orchids’, as the multi-coloured flowers resemble miniature orchids, but can be grown from seed at a fraction of the price.

The Pelargoniums, commonly referred to as ‘geraniums’ will be propagated from cuttings or potted on and pruned to tidy the display after the winter and to encourage plenty of flowers during the summer.

Now that it is warm enough, we will be releasing our first biological control of the year into the glasshouses for pest control. Biological control are various beneficial insects that prey on insects which cause plant damage. Encarsia; a tiny parasitic black wasp controls whitefly, Cryptolaemus; a dark brown Australian ladybird controls mealybug and a Bacillus bacteria will be used to control tortrix moth caterpillar. All of these are completely harmless to humans and have been used in the horticultural industry for decades.

After such a wet few months it will be lovely to have the sun on our faces at the start of spring. The Gardens are awash with colour: the yellow daffodils, and the blue grape hyacinths and ‘Glory of the Snow’ (Chinodoxa). Multitudes of these can be seen at ground level, if you look higher the magnificent magnolias in pink and white shine out as do the flowering cherries. There is also a hint of green on many trees as the buds are swelling ready for opening later in the month.

All the hard work of removing the old foliage on the epimediums has really paid off; the lovely, graceful flowers are now in full view above the new leaves in subtle shades of red, orange and yellow. You can see them in the Azalea Walk and around the Bandstand.

Last month was so wet that the grass seed sowing was delayed and we will start on this now. Any areas that have not recovered well from the Magical Lantern exhibits will be reseeded. The soil will be dug over again, and then lightly raked to produce a fine tilth, a good seed bed. Seed of a robust cultivar of grass, able to cope with heavy traffic will then be broadcast over the area and lightly raked. A good hand full of seed will be spread over each square yard. If the weather stays dry we will have to water but, hopefully there is enough ground water to allow germination. You may see some temporary fencing appear around the areas to allow the seed time to germinate and grow without disturbance.

Grass cutting is going to start in earnest now the weather is warming up, the first few cuts will leave the grass slightly longer, save stressing it out and pulling it out of the ground. We are trying to cut the grass when the early morning moisture has evaporated so that the mower does not smear the soil around when the mower and the roller turns on tight corners.

We are also going to be sowing our wild flower meadow by the duck pond as soon as we have rotovated the soil.

The new herbaceous border planted last autumn is now showing signs of growth and it has already been weeded once. The second larger portion of the border is going to be treated with weed killer as soon as the weather is dry. Other areas of hard standing that have become weedy will also be sprayed with weed killer to keep them looking tidy.

Our new roses for the bare areas in the Rose Garden have been ordered and will be planted, into the recently manured beds. The roots will be treated with a mycorrhizal drench to help them grow away quickly. It does work the proof is there in the beds planted over the last couple of years.

We are also gearing up for the bedding out season, dahlias, salvias, cannas and bananas are being brought into growth ready to be planted out in May, and our summer bedding plants are arriving as small plugs, ready to be planted into larger pots with plenty of food.

Finally, we would like to wish you happy Easter and hope to see you at the Gardens, taking in the spring sunshine and joining in the many activities arranged for the Easter holidays. You can read more about them here: http://www.birminghambotanicalgardens.org.uk/events/easter-half-term-fun-2017/