High summer is upon us! Here are our top jobs for July.
The most important thing you can do for your plants in hot weather is water them! Water your pots daily in this very warm weather and every few days otherwise. If you poke your finger into the compost and it’s dry around an inch or so down, it’s a good bet the pot needs water. Make sure you water into the soil/compost, not just over the leaves of the plant. Even when we do get some wet weather again, rainfall usually fails to get into pots as the plants block the soil and the rain rolls off the leaves, so be sure to keep them well watered over the coming months.
We recommend having a water butt to recycle rainwater if possible. These can be fitted to downpipes on the house or on sheds/garden rooms/garages and are well worth looking into if you haven’t already got one.
As well as watering your pots, it is also essential to water newly planted plants. We had a particularly dry winter and many plants – including evergreens – are really suffering from this now, especially in the current heat. Anything planted 18 months or less ago will still need watering regularly to help them establish (every 1-2 days for those planted this year, and 2-3 days for those planted last year).
Container grown plants will benefit from a feed every few weeks. Little and often is definitely better than a lot in one go, and take care because overfeeding can damage the plants. Many websites recommend weekly or fortnightly feeds. We find this can sometimes be a little much if using strong fertilisers so we recommend using a homemade feed or liquid seaweed. These are also more environmentally friendly.
Feeding is necessary during the plants’ growth period because container grown plants are unable to search for nutrients in the soil like ground grown plants do. Usually the starter nutrients in compost lasts around six to eight weeks so there is no need to feed newly planted pots until this time is up. For plants that are long term pot dwellers, regular feeding will go a long way to keeping them healthy.
There are many types of feed available. We suggest using organic feeds rather than inorganic. This means naturally derived feeds rather than synthetically produced plant nutrients. All feeds have three main components – nitrogen, phosphorus and potassium. The ratio of these varies from product to product as different plants require different ratios. You can google the needs of your specific plants but as a rule of thumb – high nitrogen feeds promote lots of leafy growth which can be at the expense of flowering, so for flowering plants at this time of year (roses and sweetpeas for example), and for fruiting plants (tomatoes for example) a feed higher in potassium is a good option. Organic liquid seaweed feed is an excellent all purpose choice.
If you are able to make your own feed you can use the leaves of comfrey or even the green alkanet that we have recommended removing below. You need to chop the leaves up and place them into a lidded container. Pack the leaves in and weigh them down with a large stone or brick. Put the lid on and leave to rot. The liquid produced in this process is the liquid feed. It’s smelly so best not kept near the house! Check on it every few weeks and pour out the liquid into a container. You can add more leaves at this time too. When using the feed, roughly use one part comfrey to ten parts water.
PRUNE SYRINGA (Lilac)
Now that the flowers on your Lilac have faded you can deadhead them to stop them looking a little unsightly. You can also do a light prune of the shrub to maintain its desired size and shape – if left to reach their full size, the flowers tend to be too high to see and most importantly smell! However, as flowering occurs on the previous year’s wood you do need to be careful not to take too much off all of the stems – just enough to control the shape. As usual with pruning, remove any dead, damaged or diseased wood and if you have two crossing stems pick one of them to remove. Please note, regenerative pruning for leggy or very overgrown shrubs should wait until the winter when the plants are dormant. However, if you have congested stems around the base you could remove a few of the oldest stems now. Cut these back to the base and your plant will thank you for the additional airflow.
PRUNE CLEMATIS ARMANDII
This evergreen clematis is fast growing and comes under Pruning Group 1. This means it doesn’t need pruning to thrive, only if its size needs to be managed. Prune it to the desired size and cut back to just before a leaf.
PRUNE CEANOTHUS, PHILADELPHUS AND WEIGELIA
Spring flowering, evergreen ceanothus will have finished flowering now. They only need a light prune, if anything, to help maintain shape and size. Side shoots and any dead, damaged or diseased stems can be removed. Later flowering and deciduous varieties shouldn’t be pruned now but rather in the Spring.
Philadelphus and weigelia can be pruned now that they have finished flowering. Take off around a third of each of the flowering stems, cutting back to where you can see new growth emerging. You should also remove around 20% of the oldest stems from the base of the plant to promote air circulation and reduce overcrowding.
KEEP ON TOP OF PERENNIAL WEEDS
As ever, we encourage you to only remove weeds that are competing with intended plants, or that can quickly dominate a planting area. Couch grass, bindweed, ground elder and green alkanet are four such plants that it is sensible to keep on top of.
Green alkanet is great for wildlife but can become very dominant and hard to remove if left to establish in planting beds. It’s a pretty wildflower that we do recommend leaving in some wilder parts of your garden if possible. It provides food for caterpillars and is a valuable provider of nectar too. It can however quickly establish itself and outcompete intended plants. It has a long tap root that can easily be snapped if pulled. It is best to dig the plant out to ensure as much of the root is removed as possible, otherwise it will keep growing back. If you do intend to keep some of it, you may want to deadhead just as the flowers are going over to avoid it self seeding.
Bindweed should be removed because it can choke other plants as it winds around them to climb. Again, care needs to be taken to remove as much of the root as possible. If it is not possible to dig out the roots of bindweed – for example because they are too close to other plants – regular hoeing or pulling is needed to prevent the growth establishing. If you do have bindweed check on the areas every week if you can to remove new growth as soon as possible.
Couch grass spreads via rhizomes underground. The problem is these can quickly take over beds, and also become entangled in the roots of your perennial plants and shrubs, causing them damage. As much as possible, couch grass should be dug out. One of our favourite tools, a hori hori, can be very helpful for removing the roots.
Ground elder is fast growing and can easily crowd out slower growing, smaller plants. It has a long white root that needs removing to prevent it from growing. Again, this can snap off easily so a hori hori can be a great tool to use to remove small plants, but a garden fork will be needed to dig out and successfully remove established clumps.
Don’t compost these weeds as the rhizomes will live on in the compost and then regrow. Instead add them to your council compost bin.
If you are noticing some container plants are failing despite being well watered it could be down to Vine weevil larvae. They become active around now and will eat the roots of plants. They are about 1cm long, white larvae with a brown head and often in a C shape. Have a check around the roots of affected plants and if you find any you can remove them. If there are lots you may wish to consider using a biological control of nematodes to get rid of them.
KEEP TYING IN CLIMBERS
Climbing roses, sweetpeas, clematis, jasmines and other climbers really benefit from being regularly tied in – once a week if you can manage it. This allows them to focus energy on growth and decreases the chance of stems snapping. It also allows for their growth to be directed so if you are trying to cover a wall or fence, create a flower-filled archway or cover a pergola, tying them in the direction needed is essential.
With sweetpeas, you can pinch off the tendrils as they aren’t needed for support once you have tied them in. They will cling to anything including their own stems and can restrict growth, become tangled or damage neighbouring plants. It’s also important to regularly water sweetpeas as they are thirsty plants. As soon as they start flowering, be sure to cut the flowers to enjoy in the house, or deadhead regularly. You don’t want to let them go to seed as once this happens they will stop producing flowers and start to die back.
SUPPORTING TALLER PLANTS
Providing stakes for taller plants like delphinium, hollyhocks, dahlia and even sunflowers is always a good idea. If you didn’t do this during earlier growth and now have floppy plants, you can always add bamboo or willow canes, or you can use a half hoop plant supports which are more easily added into established borders and can help to stop plants flopping over pathways too.
DEADHEAD ROSES, SALVIA, GEUMS AND PENSTEMON
Keep removing spent flowers from roses, salvia, geums and penstemon. Not only will this help the plants to look tidier but should promote more flowers. With roses, cut the flower heads off to the next set of five leaves, oir for leggy stems give them a harder prune to maintain good shape. With geums you should remove the whole flowering stem down to the base or to where a new flower is developing. Penstemon can be cut down to healthy looking leaves below the spent flowers.
Whilst there are several different types of salvias which do need different treatment in the spring, at this time of year you are just removing the spent flowers down to a healthy looking set of leaves (look out for new growth and flower heads emerging).
CUT BACK HARDY GERANIUMS AND NEPETA
This seems drastic, but if you would like a second flush of flowers on your hardy (perennial) geraniums, they can be cut back to the ground and they will regrow and flower again this season. Using shears, cut back all the foliage after the first flush of flowers is finished, and give them a good water. They will regrow in no time. You can of course choose not to do this if you don’t want the gaps in your borders, but you can plant annuals into the gaps such as cosmos and zinnia if you would like. Just make sure you don’t plant too close to the geraniums so they have enough light and space to regrow this season by the end of summer.
With Nepeta, you will be able to spot where the new growth is emerging from the ground, and you can simply cut the spent flowering stems back to allow the new growth to take their place.
FILL BIRD BATHS
Bird baths provide an important water source during the dry summer months. Birds drink from them as well as bathe so make sure to keep it clean and topped up. It’s best to keep them away from bird feeders so food doesn’t drop into them and be sure to have a raised one if cats frequent your garden.
With all the warm weather, ponds will need topping up with water. It is best to use rainwater for this, so if you have a waterbutt you can use this to top the level up. If you don’t, you can fill some buckets (several of a size you can manage to carry when full of water) with tap water and leave them to stand for a couple of days. This allows the chlorine to disperse. If you aren’t able to do this, you can use a hose but be sure to put it on the spray setting and to allow the water to pass through the air before going into the pond so as to allow the chlorine to disperse.
Blanket weed, pond weed and any overgrown or crowded submerged foliage can be gently removed and laid next to the pond for a day or two to allow any insects or newts to find their way back to the water. The weeds can be added to your compost heap.
We hope this helps you to keep things in shape this month. Happy gardening and keep cool!