Physical presence in the garden is one of the most important tools in the gardener’s toolbox. But when we are on a vacation, this tool in our garden is obviously absent.
It takes courage to go on vacation in the hot months of high pest activity. What steps should conscientious rosarians take in their garden prior to an vacation, especially one that is scheduled during the hot weather months? And what do we need to do on our return?
Pre-vacation checklist
1: Run and watch each station on the irrigation system to make sure all plants are getting watered.
2: Check the drip emitters on container plants to ensure that they are functioning optimally. Check the 10-day weather forecast and determine whether to increase the irrigation run time and/or the number of irrigation days. In hot areas, position movable containers to a shadier area or put up a shade cloth.
Adult lacewing on ‘Princess Alexandra of Kent.’ Lacewings are hugely beneficial in our garden. (Rita Perwich)
3: For any plants that need to be hand watered, enlist a friend to water. Plants are just as easily killed with too much water as with too little water, so if your friend is a nongardener, be very specific about how much water to apply and how often. Ask your friend to replenish water in your fountains so thirsty birds are not disappointed.
4: Cut blooms and make bouquets for your friends.
5: Deadhead spent blooms and pick up all debris in the garden.
6: Cut out cluttered inward growth to improve air circulation and minimize pests and disease.
7: Remove all weeds.
8: Stake plants that look like they might need .
9: Mulch your soil to keep moisture in and cool the soil.
10: Patrol for pests and remove them from the garden. Pest populations differ each year: Last year, I barely noticed any rose slug damage in my garden, but this year has been the “Year of the Rose Slug.” I have been seeing lacy leaves, the rose slugs’ unwelcome signature and a sure clue of their presence, in my garden and in many neighborhood gardens. Rose slugs are the larvae of sawflies and look like (but are not) green caterpillars. They are hard to see as they feed on the underside of leaves. Several weeks before my trip, I cut out all infested leaves with the hope that my dedication would eradicate or at least put a big dent in their population and life cycle.
Post-vacation checklist
My post-vacation bliss was abruptly disrupted with the disagreeable sight of a sea of lacy rose leaves throughout my garden. But there was a silver lining. The close-up work spent cutting out rose slug damage led to many productive discoveries, both good and bad, and enabled me to let go of my rose slug angst.
Your post-vacation checklist includes scouting for and eliminating pests, practicing good rose culture and looking out for garden beneficials.
Find and eliminate pests
I did not see all the following pests, but when the weather is hot and you see damage, these are the main culprits:
Rose slugs: We can squish rose slugs or we can remove the damaged leaves. The latter is preferable for aesthetic reasons, provided the rose is vigorous and has sufficient leaves. It is better to use our pruners and cut the leaves off the bush rather than stripping the leaves off, which risks wounding the stem and can provide an entry for infection by fungal spores.
Caterpillars and inch worms: These feed on rose leaves and buds. Clues of their presence are chewed-up buds, blooms and leaves, their frass and folded-over or silked leaves. Cut out damage and squish the culprits you see.
Grasshoppers: They come in all sizes and colors and are very destructive chewing pests of leaves and blooms. It is hard but enormously satisfying to catch these highly mobile pests.
Aphids: The soft-bodied pests suck on tender new leaves, stems and buds. They are easily squished with our fingers or knocked off with a strong spray of water.
Scale: These feed on rose canes and stems with piercing mouth parts. They are easy to eliminate when we discover them at their newly hatched, white, soft-bodied crawler stage.
Green fruit beetles: The beetles are easy to spot because they are iridescent and buzz and zoom loudly around roses and fruit trees. Focused while they feed, they are easy to catch and drop in a bucket of soapy water.
Spider mites: These are hard to see, but the telltale sign of their sucking presence is stippling of the leaf and webbing on the underside of the lower leaves. If you find them, you can control them with jets of water applied forcefully every three days to the underside of leaves.
Chilli thrips: These are the nightmare pest in California rose gardens. You cannot see them with the naked eye, but their damage to new growth and buds and blooms is immense. Chilli thrips larvae and adults extract sap with piercing and sucking mouthparts, leaving deformed and crinkled new foliage with dirty brown scarring on the back of the uppermost leaves. Ugly, scorched and deformed blooms and brown or bronzed-tinged buds are additional signs of their ravaging handiwork. All chilli thrips’ damage must be IMMEDIATELY cut out and bagged and thrown away in the regular trash.
Practice good rose culture
Remove blind shoots: Not every stem produces a bloom. A blind shoot terminates in leafy growth in place of a bud. If the blind shoot is on the outside of the bush with healthy leaves, we cut back the blind tip above one of the leaves to allow the plant another attempt to bloom. If the blind shoot is growing toward the inside of the bush, we remove the entire blind shoot stem to promote air circulation and thwart pest hide-outs.
Deadhead: Spent blooms are the look of an unkempt rose garden. In the heat of summer, we aim to maintain as much foliage as possible on the plant and deadhead no lower than the first outward facing five-leaflet leaf. On small, struggling roses or very new roses, we cut off just the bloom and leave all the foliage. Remove old petals and brown leaves that have got caught up in the rose bush.
Remove suckers: Stems that grow from the rootstock and not from the bud union of grafted roses will diminish the growth of the purchased rose and eventually take over. Locate the origin of the sucker below the ground and tear it off so the growth will not resprout.
Wash the leaves: We should provide heat- and wind-stressed plants some relief by showering their leaves with water. This action also keeps pests like spider mites and aphids in check and helps us blast out hard-to-reach old brown leaves caught up in the rose bush. Avoid the hottest hours of the day to minimize loss of water to evaporation but allow sufficient time for the leaves to dry off before nightfall to prevent water-initiated fungal diseases. It is a myth that watering plants on a hot sunny day will scorch their leaves.
Basal breaks: Discovering basal breaks early gives us an opportunity to protect this soft and easily damaged new growth. Cut out old, less desirable growth to create optimal space, sunlight and air circulation for our plant’s new productive canes.
Embrace delightful garden friends
I happily reaffirmed during my post-vacation up-close inspection of my garden that there are many beneficial friends who are busy at work in controlling pests in my garden. I discovered many lacewings, lady beetles, lady beetle larvae and syrphid flies in my garden. Attached to the undersurface of many, many leaves in my garden I found pale green lacewing eggs, each suspended at the end of a slender silken thread. Each delicate lacewing egg hatches into an alligatorlike larva that consumes a multitude of soft-bodied prey including aphids, mealybugs, scales, chilli thrips, thrips, leafhoppers, and spider mites and their eggs.
Don’t hesitate to take vacations! Healthy gardens are under the patrol and watch of birds, spiders and beneficial insects. We can go on vacation and depend on their immense hunger for pests. Post-vacation, the pests quickly discover that the resident gardener is back, vigilant, in control and unceasing in their demise, and your garden will soon bounce back from any setbacks.
Perwich is a member of the San Diego Rose Society, a Consulting Rosarian and a Master Gardener with UC Cooperative Extension.
