What to do in a Desert Garden in May?

There are tips on what to do in the desert garden this month from the
University of Arizona College of Agriculture Maricopa County Extension
There's also a lot of other helpful information and FAQ's on that website.
Another site of interest on what to do in the garden here in the low
desert is John Chapman's site.

Climate Information for May
in Phoenix, Arizona
Rainfall:

Average: 0.1 inches
Record: 1.3 inches (1930)

Temperature (degrees F):

Average High: 93.6 degrees
Lowest High: 54 degrees (1915)
Record High: 114 degrees (1910)

Average Low: 63.9 degrees
Highest Low: 86 degrees (1983)
Record Low: 39 degrees (1899)

Note: Rainfall and temperatures vary widely within the valley depending upon elevation and microclimate.

To Do List . . .
Turf

Plant Bermuda lawns when soil warms up in mid to late May.

Fertilize Bermuda grass lawns each month beginning late April or early May with nitrogen according to the directions on the package.

Apply Iron each month according to the directions on the package.

Apply one inch of water per week to Bermuda lawns

Once every two or three years dethatch Bermuda lawns if necessary. Only dethatch during the active growing season, May through August. This enables the turf to quickly recover.

Vegetables

Plant Seeds
Black eyed Peas, Melons (Cantaloupe, Muskmelon), Okra, Sunflowers

Plant Transplants

Jerusalem Artichokes, Sweet Potatoes

Place shade cloth over tomatoes.

Roses

Continue fertilizing established roses, liquid fertilizers can be added at 2 week intervals, follow the directions on the container.

Fruit and Nut Trees

Plant Citrus Trees - Young two to five year old trees transplant most successfully. Larger, older trees are more costly, harder to transplant without injury (to yourself and the tree), and suffer more from transplant shock. It will generally be three years after transplant before fruit production and that is the same whether you plant a 2 year old tree or a 10 year old tree. Go small!

Pick early-maturing deciduous fruit varieties, which are particularly prone to bird damage, before full maturity. Ripened at room temperature to lessen the bird peck loss.

Cover fruit trees to protect from birds

Give special attention to watering deciduous fruit trees, provide adequate soil moisture for fruit sizing in the late April and May period.

Apply nitrogen and zinc to pecan trees to produce normal size leaf growth and to enhance kernel development. Pecans also need more water than most other shade trees.

Landscape Plants

Increase water application as the weather warms.

Tree water use, desert types being the exception, increases rapidly during this period of leafing out and gradually higher air temperatures.

Apply mulch to the ground around heat sensitive plants keep the roots cooler and prevent evaporation. Be sure to keep the mulch several inches away from the trunk to prevent pest and disease problems.

Apply chelated iron to bottle brush, pyracantha, silk oak, and other plants with iron deficiency symptoms.

Prune palms when flower spathes show or delay pruning until after the palm has finished flowering to prevent infestation of Palm Flower caterpillars. If palms are pruned in the spring, leave the top five rows of peels so the caterpillars have a place to hide.

Don't List . . .

Do not prune citrus except to remove dead or damaged wood and branches obstructing pathways, views, or structures.

Do not use pre-emergent herbicides in an area in which you intend to plant seeds.

Frequently Asked Questions
Damage is Noticed on the Fruit

Tomatoes have a large soft rot at the blossom end of the fruit

Citrus fruit drop

The shed of newly set fruit is a natural thinning worsened by hot weather and dry winds. There is no cause for concern.

There are large bright red and black or all black bugs on my fruit

Vegetables are not setting fruit

Many of our helpful European honey bees have been annihilated by people trying to protect themselves from Africanized honey bees. In addition, many bees have been killed by mites. As a result they are not available to assist with pollination. Squash, melons, cucumbers and other vegetables that have separate male and female flowers will benefit from hand pollination. Early in the morning use a cotton swab to take pollen from the male flower and place it female flower.

Damage is Noticed on the Leaves

Leaves are abnormally yellow but the veins are still green

Citrus leaves are curled and/or the fruit is slightly scarred.

Leaves of vegetables (particularly cabbage, broccoli, cauliflower etc.) being eaten by snails, slugs, cabbage loopers, or birds.

There are lots of aphids, tiny insects, on my plants

The leaves or needles have yellow spots or stippling. Leaves are stunted and twisted. There is a fine webbing between leaves.

A shiny little bug is destroying Mexican Evening Primrose, Dichondra, or vegetables

Something is devouring the grape leaves, only the veins remain.

Bermuda grass is turning yellow-brown and dying in patches, there are tiny white flecks in the soil around the roots

There is a gray or white powdery substance on plants

Seedlings and bedding plants wilt and die suddenly

Damage is Noticed on the Stem or Trunk

Pines are dying back from the tips
This is a probably a physiological response. Check the soil near the trunk. Those with circling roots exhibit the worst symptoms.

There are lots of aphids, tiny insects, on my plants

There are brown balls/galls on the stems of oleander

Dry, thin bark cracks and splits to reveal black, powdery spores. Foliage above the wound is sparse and leaves may be small. Eventually branches die back to the canker.

Leaves, twigs (and in advanced stages, branches) of pears and pyracantha are dying back from the tips with a scorched appearance

Saguaro cactus has large black patches that are oozing and smell terrible

Damage is Noticed on the Roots Cultural / Environmental Questions

Tomatoes and or Peppers have a large soft rot at the blossom end of the fruit

Citrus fruit drop

The shed of some of the newly set fruit is a natural thinning worsened by hot weather and dry winds. Unless it is extreme, or there are additional symptoms there is probably no cause for concern.

Leaves are abnormally yellow but the veins are still green

Pines are dying back from the tips

This is a probably a physiological response. Check the soil near the trunk. Those with circling roots exhibit the worst symptoms.

Insect/Pest Questions

There are large bright red and black or all black bugs on my fruit

Vegetables are not setting fruit

Many of our helpful European honey bees have been annihilated by people trying to protect themselves from Africanized honey bees. In addition, many bees have been killed by mites. As a result they are not available to assist with pollination. Squash, melons, cucumbers and other vegetables that have separate male and female flowers will benefit from hand pollination. Early in the morning use a cotton swab to take pollen from the male flower and place it female flower.

Leaves of vegetables being eaten by snails, slugs, cabbage loopers, or birds.

There are lots of aphids, tiny insects, on my plants

Citrus leaves are curled and/or the fruit is slightly scarred.

The leaves or needles have yellow spots or stippling. Leaves are stunted and twisted. There is a fine webbing between leaves.

A shiny little bug is destroying Mexican Evening Primrose, Dichondra, or vegetables

Something is devouring the grape leaves, only the veins remain.

There are hundreds of small gray bugs in the yard, some are even coming in the house

Bermuda grass is turning yellow-brown and dying in patches, there are tiny white flecks in the soil around the roots

How do I get rid of Black Widow Spiders?

Disease Questions There is a gray or white powdery substance on plants

Seedlings and bedding plants wilt and die suddenly

There are brown balls/galls on the stems of oleander

Dry, thin bark cracks and splits to reveal black, powdery spores. Foliage above the wound is sparse and leaves may be small. Eventually branches die back to the canker.

Leaves, twigs (and in advanced stages, branches) of pears and pyracantha are dying back from the tips with a scorched appearance

Saguaro cactus has large black patches that are oozing and smell terrible