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5 problems in the late spring garden

Summer's essentially here, and bringing its challenges

Sacramento Digs Gardening
BY Kathy Morrison PUBLISHED JUN 4, 2026

The navel orange tree these fell from is self-editing, reducing the number of oranges it can support before summer hits. The tree may still need some hand-thinning. Kathy Morrison

The weather's heating up. Hot weather stresses plants. How the resulting problems are handled often separates the casual gardener from the experienced one.

Here are five common problems in the garden right now. Most are normal, at least one may need immediate attention:

-- Why is my orange tree dropping so much of its little fruit? This is known as "June drop," although it can happen in May or July, too. The tree does some natural thinning of the small pollinated fruit. It's rather like checking your bank balance, then removing items from your grocery cart. Don't need it, don't need it, don't need it.

This thinning can happen with other fruit trees, although it seems most dramatic with citrus. Make sure the tree is receiving adequate water. Also, if many leaves are turning yellow, it may be nitrogen-deficient. (A few yellow leaves is normal.)

Citrus and other fruit trees may still need some hand-thinning before the fruit gets bigger than 1 inch in diameter. Too many on one small branch can bring down the branch, harming the tree's health and reducing the year's crop.

-- Why are the leaves curling on my tomato plants? The easiest answer is that it's not watered enough. The leaf curling is the plant's way of protecting itself, lessening the amount of water lost to transpiration. Tomato plants thrive on deep, infrequent watering, sending out their roots deep into the soil. Frequent short irrigation times do very little to develop long roots, and the plants will become more stressed as the temperatures rise. There are other, more serious reasons leaves will curl, but if the plant looks healthy otherwise, at this time of year the answer is likely watering.

-- Speaking of tomatoes, one of the plants has some yellow leaves with brown or black spots. What's wrong? Oh, now this is not something to ignore. There are several diseases that can cause spots, including early blight, which we don't usually have to deal with in our dry summers, but the May rain we received may be the culprit here: Early blight is spread by splashing water and germinates on moist leaves. Cut off the infected leaves and dispose of them; do not compost. Avoid overhead watering.

The other possible diseases are bacterial spot or bacterial speck. These diseases also can be spread by overhead watering, splashing rain or working with wet, infected plants. Handle the diseased leaves just as with early blight.

In all of these cases, warm, dry weather will reduce the spread of the disease. Make sure the plant stays healthy: Stress invites pests (such as spider mites) and other diseases.

-- One more tomato problem: The plant has flowers, but it's not setting fruit. What's happening? Tomatoes like warm weather, but heat spikes (over 95 degrees) will dry out the pollen, preventing fruit set. Also, tomatoes are wind pollinated. Help them out by flicking the open flowers with your fingers. (Don't waste money on blossom-set spray -- it's effective at low temperatures, not high ones.) See more advice on tomatoes and heat here

-- Why do my squash plants wilt in the afternoon? Remember those curling tomato leaves? Squash plants (and pumpkins and melons) also react to afternoon heat by reducing their leaf surface. Wilting leaves in the afternoon are not worrisome; wilting in the morning hours means the plant needs water.

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tomatoes oranges diseases spring summer June heat rain weather vegetables citrus irrigation Sacramento gardening

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Flowers in My Back Yard Series

Aug. 25: Crape myrtles, Sacramento's unofficial tree of summer

Aug. 18: Pollinators adore scabiosa, aka pincushion flower

Aug. 11: Hardy hibiscus adds big tropical impact

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July 28: Naked Ladies put on summer show

July 21: Thank Luther Burbank for these long-lasting beauties (Shasta daisies)

July 14: How to keep hydrangeas happy

July 7: Grow these bright cosmos for bees and butterflies

June 30: Agapanthus adds blue fireworks to the garden

June 23: Easy-care gazanias fill those hot corners

June 16: Daylilies are perfect for water-wise gardens (and a lot more)

June 9: Grow coneflowers for pollinators -- and yourself

June 2: Sunflowers capture Sacramento's summer attitude

May 29: Are your roses going 'blind'?

May 26: Zinnias are the summer flowers every garden needs

May 19: Plant dahlias now for late-summer flower power

May 12: Know your coreopsis from your bidens

May 5: Mums the word on Mother's Day weekend

April 28: Majestic Matilija poppy is worth a look

April 21: Celebrate roses, America's favorite flower

April 14: Small flowers with outsized impact

April 7: Calendulas do double duty

April 3: Make Easter lilies last for years to come

March 31: In praise of a pollinator magnet (small-leaf salvias)

March 24: Azaleas brighten shady spots

March 17: The perfect flower for beginners? Try zonal geraniums

March 10: Keep camellias happy for years to come

March 3: Fruit tree blossoms are a fleeting joy

Feb. 27: Are your roses looking rusty?

Feb. 24: Treasure spring daffodils now and for years to come

Feb. 17: How and why to grow wildflowers

Feb. 10: Let's talk Valentine's Day roses

Feb. 3: Why grow flowers?

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Garden checklist for week of Aug. 16

During this break in the heat, feed your garden. Make sure to water before and after applying fertilizer.

* In the garden, direct seed beets, carrots, leaf lettuce and turnips.

* Plant potatoes.

* Harvest tomatoes, beans, squash, pepper and eggplants to prompt plants to keep producing. Give your plants a deep watering twice a week, more if planted in containers. Also, give them a boost with phosphate-rich fertilizer to help fruiting.

* Watch out for caterpillars and hornworms in the vegetable garden. They can strip a plant bare in one day. Pick them off plants by hand in early morning or late afternoon.

* Feed citrus trees their last round of fertilizer for the year. This will give a boost to the fruit that’s still small.

* Mulch can be your garden’s best friend – it conserves moisture while blocking out weeds. But don't let mulch mound around stalks, stems or trunks. That can promote rot.

* Camellia leaves looking a little yellow? Give them some chelated iron. That goes for azaleas and gardenias, too.

* Pick up after your fruit trees. Clean up debris and dropped fruit; this cuts down on insects and prevents the spread of brown rot. Then feed fruit trees with slow-release fertilizer for better production for next year.

* To prolong bloom into fall, feed begonias, fuchsias and container plants. Always water before fertilizing.

* Fertilize fall-blooming perennials, too. Chrysanthemums can be fed until the buds start to open.

* Prepare for a fall full of flowers by paying a little extra attention to your garden. Cut off spent blooms from roses, annuals and perennials, then give them a boost of fertilizer. Make sure to water plants before feeding. Roses will rebloom about six to eight weeks after deadheading.

* Indoors, start seedlings for fall vegetable planting, including bunching onion, cabbage, broccoli, cauliflower, kale, radicchio and lettuce.

* Sow seeds of perennials in pots for fall planting including yarrow, coneflower and salvia.

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