i would think that would work fine I have used a similar set up on new beds. I guess it would really depend on the plantings. I would try it out and see how the water flows before you put the mulch - but i would use mulch for sure

I think I have an answer to your problems. Though we are helping the poor developing countries, where there are acute water shortages.
In your case, it very easy to irrigate flowers , perhaps once in a week or fortnight. Here is the systems. You can email for free details.

SAPAM WET IRRIGATION TECHNOLOGY

AUSTRIA

FREE to NGOs & International Help Organisations, Togather with Important piping material
( free of charge) for one complete Pilot Project for Each NGO, with simple method of preparing
the piping by villagers themselves, to start Wet Irrigation System.

This paper is dedicated to the POOREST OF THE POOR, where there is a shortage of irrigation water and resources are limited, So that no child should live with MALNUTRITION and eventual deaths. If the goals of M D G ( UNO millennium Development Goals ) are to be achieved, then the poor villagers with small piece of land, have to be provided with some workable and cheap irrigation technology. Drip irrigation has notable successes to report (unfortunately beyond the reach of very poor villagers), but wet irrigation saves 75 - 80% water against flood and other systems, and save up to 35 % against the best known Dip Irrigation.
IMPORTANT :- Wet Irrigation System COST A FRACTION of Drip System.

Wet irrigation of roots occurred to me, when I saw weed breaking through the cemented path in our garden. I asked myself " If the plant roots are so strong to break the concrete, then those must be strong enough to suck wetness and moisture from distant water source to over live and get stronger. So, we started working on Wet Irrigation System and were overwhelmed and pleasantly surprised to see The RESULTS EXCEEDING OUR EXPECTATIONS.

First experiments were carried out, on Hundreds or perhaps thousands of years old WICK & POROUS CLAY POT Irrigation system. This confirmed our belief that the plants can suck
Water from great distance. ( DENMED et.al.1962)

Our greatest concern was the scarcity of cultivation water in the poorest areas of Africa and Asia.With the Porous Clay Pots and Wick Irrigation, the whole area had to be kept wet, for plants to suck water according to their needs. In wet irrigation, BURNT CLAY PITCHERS (or plastic Used bottles) are used to stop any seepage through the pot ( or bottles). Secondly, material waste is covered with Food quality thin plastic piping, so that the water sucked underground and transported, reach the plant roots directly. There is NOT EVEN ONE CENTIMETER
of earth is being made unnecessarily wet, wasting scarce water.

Wet Irrigation technology is simple and cheap to install. Unlike all other irrigation systems, where the water is provided to the soil, thereby a high percentage of water get evaporated through Sun, high temperature, wind and other factors. Sapam wet irrigation provide, under earth, wetness around the area of the roots, thereby avoiding any evaporation and loss of water, and eliminate weed growth.

At times of draught and failure of rains etc. the ancient religions like Confucianism, Taoism and Hinduism mention " MULCHING" of cultivation land as a solution to hunger and famine. There were different kinds of mulching methods, which are at todays concept not suitable or workable. But the principle adopted is the same, to derive wetness from whatever source of water availability. The most important experiments carried out, during last 30 months, were to derive and deliver the wetness from distant water resources and from deep lying mulch, to the roots of the plants. Finally, waste of fibre material, covered with thin plastic piping) worked perfectly.
OUR MOTO:- DonÂt give poor people " ONE FISH A DAY TO EAT "Give them a fishing rod and teach them the methods of catching fish, for family and rest to sell for money.
Agricultural scientists suggest mulching of the soil, to save water. This is a part of wet irrigation.